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All about: medical tests | medical exams [5]


Medical Tests

  • What is a mammogram
  • What is gastric lavage
  • What is the proof of the tilting table
  • What is the Fna (fine needle puncture aspiration)
  • What is PCR (polymerase chain reaction)
  • What is polysomnography / sleep study
  • What is a study of evoked potentials
  • What is the Prick test: allergy skin tests
  • What is the breath test
  • What is a pulse oximetry

What is a mammogram?

Mammography is an x-ray of the breast that can detect the presence of breast cancer early. It is a special x-ray, as it emitted a dose very low radiation, and is capable of detecting suspicious lesions of cancer even less than 100 microns in size.

When should I get a mammogram?

There are two types of mammography, screening and the diagnostic:
Screening mammography is performed in asymptomatic women. It allows the detection of breast cancer in very early stages of its development, so it increases the likelihood for curative treatment at an early stage. Although changes in different countries, in general screening (in English screening) is recommended every 1-2 years for women between 40 and 50 years, and each year in women over 50 years. Sometimes it is recommended to perform a screening in women under age 40 with a family history of breast cancer, history of mammary pathologies, or very dense breasts. The effectiveness of screening has been shown clearly even in women over the age of 80 years.
Diagnostic mammography is performed in symptomatic, for example women when there is an abnormal the nipple discharge, when it is felt a breast nodule, or of screening mammography is not normal. Diagnostic mammography takes more time than the screening, because x-rays are performed in different positions to properly study the possible tumor and the surrounding tissue. In women with implants breast or history / personal breast cancer often are made as screening diagnostic mammography techniques to increase the sensitivity of the test.

Preparation for mammography

These are the issues that you must consider when you undergo a mammogram:
Duration: the test takes about 15-30 minutes.
Entry: the test is done on an outpatient basis.
Is necessary to be accompanied?: don't have to be accompanied by although it might help if it makes you feel more relaxed.
Drugs: is not necessary to take any prior medication. You can take your usual medication.
Food: don't have to go on fasting.
Clothing: can wear any clothes desired but something that is easy to remove, because you will be asked to leave bare should be chest. Nor should carry metal objects (earrings, bracelets, etc.) because they will be asked to remove them during the test.
Documents: can carry previous reports with information about their health, and mammograms earlier if it is necessary to compare them with that is to be performed.
Contraindications: there are no absolute contraindications. It is not usually done in women below 30 years because breast tissue is denser and the test is not reliable. It is advisable to inform the physician of the possibility of being pregnant or if it is giving suck.
Pregnancy and lactation: the realization of a mammogram is considered safe during pregnancy and breast-feeding because the radiation dose is very low. However, moms are more dense during pregnancy and lactation, so the test is less reliable. You should consult your doctor about the risk and profit making, or postpone the test, or the possibility of replace it with other evidence such as breast ultrasound.
Other considerations
Do not use deodorant, talcum powder, or any type of lotion or cream on your breasts or underarms the day of the test, as it could interfere with the result of the same.
The best time to perform the test is one week after the rule as it is when your breasts are least sensitive.
It should inform the physician of the use of hormonal, background on breast surgeries treatments, or if you have personal or family breast cancer history.

How is a mammogram

For the realization of the mammography you will be asked to undress and remove jewelry and metal objects from the waist up. They provide a disposable gown to cover. It examines each breast individually. To do so, compress the breast between two sheets of plastic. This compression allows to obtain images with less radiation dose and quality of the entire breast. Usually images above are taken down and one side of the breast to the other. They may be necessary images from other positions. A few small marks on the skin are sometimes made to locate regions that should be studied closely, or skin lesions. In the moment in which the images are taken we have to remain very still and you may be asked to keep a moment breathing. The technician who takes x-ray will be in an adjacent room from which activate the emission of x-rays. After the test, you may be asked to wait a bit, because the technician will examine the images and tell you if it is necessary to repeat any of them.
  • Possible complications of this test is very limited:
  • The radiation is extremely small for what is considered a very safe test.
  • There is no rest of radiation in the body after the procedure.
  • The compression of the breast between two plates can be a bit annoying. Where compression is painful, you can tell the technician perform the test with one lower compression.

The mammogram results

Following the completion of the test, a medical specialist will carefully examine images. The result is usually available within a few days. If they don't give results in a few days, you should ask for them and not assume that the test is normal.
It should bear in mind that mammography has some limitations. You may not detect any cancer, giving rise to what in medicine we call false negatives, or can be mistakenly diagnosed cancer when there it, what we call false positives.
In general, the results can be the following:
All normal.
Discovery of a benign, non-cancerous, lesion requiring no different from the usual follow-up.
Discovery of a probably benign lesion, but that requires a narrower track.
Discovery of a lesion suspected of being malignant by suggesting it to consider carrying out a biopsy.
Finding of injury with high probability of being malignant. It is suggested to take measures for a precise diagnosis.
Your doctor will inform you about the results of the test and will instruct you if it needs new revisions or performing other procedures.

What is gastric lavage

Gastric washing is a technique that allows you to empty the contents of the stomach to avoid passing the rest of the digestive tract and is absorbed. For this purpose, a probe is inserted through the nose or mouth, and extends through the esophagus to the stomach. With this probe, the stomach contents can be absorbed (why to gastric lavage also is called 'gastric suction'), and you can get water that clean the inside of the stomach. It is a technique that carry out daily doctors or nurses in hospital admissions and emergency services. Although it is easy to make and very useful, no longer an invasive technique that should be limited to situations where it is necessary.
Throughout history man has always linked what we eat with illnesses or poisoning. Very soon saw the need to empty the stomach of toxic products or in poor condition. In the ancient Greece the emptying of the stomach was performed with substances that produce vomiting, as syrup of ipepacuana, which is still used today. In 19th century medicine began to develop gastric lavage through probing techniques, but the probes were so thick and uncomfortable that really its effectiveness rested on it caused vomiting the patient, rather than sucking stomach contents.
Techniques such as gastric lavage have allowed to save the life of many people before severe intoxications voluntary or involuntary. Its ease of implementation and its cost, have allowed to be a technique very effectively and widely used in hospitals around the world. The associated risks are rare, the most negative aspect of the technique is the discomfort for the person that is performed.

When is a gastric lavage

He is gastric lavage in the following situations:
Remove stomach accidentally ingested poisons or toxic substances.
Extract overdose of drugs, that may have been swallowed accidentally or willingly.
Check the presence of fresh blood into the stomach, to be ruled an active bleeding if not present.
Clean the inside of the stomach of blood or food before performing a gastroscopy.
Decompress the stomach inside when there is a bowel obstruction; with the probe air exits through the mouth and the stomach does not swell.
Take samples of gastric juices, to analyze their chemical composition or search for microorganisms.

Preparation for gastric lavage

If you are performing a gastric washing these are the issues that you must take into account:
Duration: gastric lavage has a variable duration according to the motives that lead to do so. You can take from a few minutes (if you want to extract toxic that they have ingested) up to several hours (to decompress the digestive tract before bowel obstruction).
Income: gastric lavage does not require an income. However, it is a test that should be done in a medical facility or in a hospital. Exceptionally, there are emergency utilities that can perform initial gastric lavage before moving the patient to the hospital. Once gastric lavage, you can return to your place of residence or stay entered, but the reasons shall be independent of having carried out the test.
Is necessary to be accompanied?: Yes, it is recommended, but not essential. Test is annoying but you not disabled, the problem is that if they have made you the test probably your medical situation may be a little sensitive, and so it is better that someone is on your side.
Drugs: don't need to take any prior medication. Should be communicated to the doctor all the medicines taken regularly and will decide which suspend or maintain. One of the reasons for conducting gastric lavage is taking excessive drugs, voluntarily or not, so it is important to tell your doctor what you have taken, when and how many.
Food: is indifferent to the test. In fact, it can be used to clean the stomach of foods that are eaten in the last hours.
Clothing: once one gets to the emergency room in street clothes is changed to a more comfortable and suitable to carry out tests and explore you gown. Clothing is recommended for sleep and comfortable shoes if you're going to join later.
Documents: it is recommended to carry the health insurance card and complete medical history. Before you undergo the intervention they will ask you if you're in agreement and if you give your oral consent, which you agree to make yourself the technique. If you are unconscious consent will give your next-of-kin or guardian.
Pregnancy and breast-feeding: gastric lavage should be limited to the second trimester of pregnancy when necessary, though in very urgent situations it may be done at any time. There is nothing that contraindicated during lactation gastric lavage.
Contraindications: the only absolute contraindication is to have any blockage that prevents the passage of the probe. Are relative contraindications uncontrollable vomiting of repetition, or do not support the probe for a few minutes; in both cases you can advertise medications that relax the patient and stop nausea.

How gastric lavage

Make you a washed stomach first make you a detailed interview about food and drugs ingested in the last hours. We will also ask you for other symptoms that can motivate the realization of the technique. In the event that you arrive unconscious, questions will be directed to your family members or companions. If you're not unconscious will regard you a sedative medication; so you'll be relaxed and discomfort of the probe nasogastric tube will be lower.
Once sedated, the doctor or nurse will introduce slowly a tube through the nose or mouth. That probe will pass through the pharynx, the esophagus will reach, and will pass through it until you reach the stomach. It is important that the probe will pass to esophageal arriving to the pharynx, and not to the trachea because, if not, would the lungs. To check that it has been placed properly be introduced a little air, which must inflate the stomach and not the lungs.
When you reach your stomach the contents is sucked and will be collected in a bag or in a transparent container that exist in the outer end of the probe. Thus the stomach contents can be seen directly and must be checked for the presence of blood, drugs, or food particles. You will only draw a few cubic centimetres of volume. If necessary it will suck more, but if you decide to clean the entire contents of the stomach saline must be introduced first.
The saline solution is passed through the tube with a syringe. Thus the stomach fills with water and diluted its content. Then she sucks and collected content. This step can be performed several times to rinse all the stomach cavity and let it clean of toxic. Sometimes the doctor will consider necessary to introduce substances that act as neutralizing the toxins ingested through the probe. The substance most used in these cases is activated carbon, which is capable of removing most of the medicines and toxic that they ingest.
When washing is completed, you can leave you probe long enough until it is checked that it is not necessary to repeat new washes or your medical situation is stable enough to stay without probe. The technique does not require you to stay longer in the emergency room, but it is likely that they prefer to be in observation at least for a few hours, to check that your body has not absorbed toxic, depending on the context.

Complications of gastric lavage

Gastric washing It is a safe and widely used technique today, but is not without risk, as it is the case with any other invasive technique. That currently use has been limited to cases in which it is necessary to do so.
The most common problems that can result are:
Minor bleeding , tear the wall of the digestive tract to the probe.
Passage of the probe to the trachea, sometimes causing pneumonia.
Spasm of the vocal cords reagent, which impedes breathing for a few seconds.
The wall of the esophagus or stomach, sometimes reaching a hole that requires surgery injury during technique .
Problems caused by sedation, as it can happen in other procedures.
Passage of gastric contents into the small intestine, to push it with the probe.

Results of gastric lavage

Gastric washing depends of if they have done it you awake or were unconscious. If you were unconscious, when you wake up you'll be drowsy, and you can have nausea. It is also normal that it hurts you throat when swallowing or you notice it a little bit asleep. Doctors will put any medication to prevent you vomites. If you were aware, you better control the symptoms and you'll notice relief to take off the probe.
Gastric contents is not usually to analyze when the toxic substance ingested is known, as in voluntary or accidental drug overdoses. Laboratory will only take when you do not know what had caused the poisoning, or when it wants to study the composition of the gastric juices by some other disease. If they have been analyzed, the doctor can give you an appointment another day, which give you the results and explain the nature of the analyzed substances.
The most important results of gastric lavage is your general State after the intervention. If the technique is successful you won't metabolic alterations, which happen when they absorb toxic by digestive tract. The doctor, moreover, tend to be analysis of blood before and after gastric lavage, leaving a margin hours. So make sure that all parameters are correct and will appreciate if you leave you leave home or enter you in the hospital for studies and subsequent tests.

What is the proof of the tilting table

The tilt table test, called in English tilt test, is used for the study of fainting or feeling light-headed. Thanks to it you can put to the test the cardiovascular system and check if it is able to respond correctly to changes in gravity, blood pressure, or heart rate. When it fails, the heart does not pump the necessary blood to the brain and a few seconds lost blood flow; It is what is known as syncope.
Such tests are carried out since the seventeenth century, but always for scientific purposes (thus studied the human nature of adaptation to changes in the environment). It was not until the year 1886 when it began to use the test with an objective diagnosis, and began to divide the blackouts between the cardiovascular and neurological origin. Today the test is still used without major changes.
Various types of sensors that record biological constants are used during tilt table test. The most commonly used instruments are:
Electrocardiogram, to study heart rate and electrical conduction.
Blood pressure cuff, to monitor blood pressure.
Intravenous, to perform a blood analysis (if necessary during the test) and injecting drugs.
With these elements the physician, which tends to be specialist in cardiology, will be able to identify the source of the problem most of the time or discard a cardiovascular cause.
It is not a particularly expensive test, but their interpretation is difficult, so must be carried out by experts, and only when you go to be useful to determine a diagnosis or deciding a treatment. It is usually done in specific cardiac units that exist in hospitals and clinics. It is unlikely that happen problems during testing, but is sometimes done to patients with a diseased heart can be altered during the procedure, and that the security measures are important.

When the tilt table testing is done

The test of the tilting table is useful when you want to test the heart and the vascular system as diseases that is altered is suspect. In any case, the main symptom of these pathologies is the fainting or feeling light-headed. Some of these diseases are as follows:
Bradycardias and electrical locks: when the heart has alterations of electric conduction heartbeat is slow, and the pumping of blood to the brain is not enough.
Syncope vasovagal: in response to different stimuli (heat, be standing a long time, nausea, etc.) it can produce a temporary blood pressure drop. This makes the blood not can promote to the brain properly and occurs the fainting.
Angina pectoris: although usually attended with pain, in some cases does not produce another symptom to the fainting or exhaustion (in diabetics, for example). Alterations of myocardial ischemia can be detected during the test.
Neurological Disorders: epileptic seizures, migraines, or transient cerebral ischemia, are some of the causes of fainting. With the tilt table test may not diagnose, but it may be one of the first steps to rule out cardiac alterations and think about such diseases.

Preparation for the tilt table test

If you are performing a tilt table test these are the issues you should keep in mind to go well prepared the day of the test:
Duration: lasts between one and two hours. Carried out in several steps and requires a preparation of material that takes some time.
Income: tilt table testing is performed in a hospital with a cardiac unit, but does not require income, by what can go that same day to the hospital, and after the test you can go home again.
Is necessary to be accompanied?: Yes, it is recommended that someone be with you. Test does not require assistance and can then only return home, but is better that someone is with you if new findings are displayed during test.
Drugs: don't need to take any prior medication. Must be communicated to the doctor all the medicines taken regularly, and will decide which suspend or maintain, especially if you take epilepsy drugs, muscle relaxants, antiarrhythmic drugs, psychiatric disorders, or antihypertensives.
Food: don't eat or drink anything 4 hours prior to the test. If you realized in the morning it is better that you go on an empty stomach.
Clothes: you can go to the quote from the test with the same clothes every day. There they will give you a Pajamas so you change and you're comfortable during the test.
Documents: is better to bring with you the steering wheel which shows the performance of this test. He is recommended to take the national document of identity and medical history on diseases to study, if you have them, although the doctor will already have it with him. Normally you will not you any document after the test because it takes time to analyze them.
Pregnancy and breast-feeding: the tilt table test is not contraindicated in pregnancy or lactation, although not perform much in those situations because the biological constants that are studied are altered for itself during these stages.
Contraindications: do test people with serious heart diseases, because the potential risks outweighed the probable diagnostic benefit.

How the tilt table test

First, the doctor will assess if it is useful to test the tilting table. In many cases of fainting do not you need to do it, because the most useful tool for getting a correct diagnosis is the clinical interview between the patient and the physician. The symptoms manifested before the fainting and the characteristics of the product can guide the therapeutic management perfectly. When you want to study the heart by a suspicion founded cardiac alterations will take place the tilt table test.
They will quote you one day for the test and explain basic measures that you need to know to submit yourself to it. The day of the test you must make a life normal, avoiding eating four hours minimum, or by going in fasting if it is in the morning. The best thing is that you get to the hospital an hour before the start of the test, to be quiet and not get nervous.
There they will give you a Pajamas to keep you more comfortable, and you will be asked you to tumbes into a sort of table or table in horizontal position and face up. They will be placed for a number of sensors in the skin of the chest, arms and legs; It is the electrocardiogram. Also they give you a small puncture in one of the elbows to put an intravenous line, and in the other arm placed you cuff of the sphygmomanometer. Then you will see that all the instruments work and properly capture measures to study. Before starting the test you will surround with a few belts to keep you tied to the stretcher. Don't worry, thanks to them you will not fall from the table when lean.
The first part of the test is carried out without drugs. It consists of tilt table 30 °, with the head slightly higher than the feet. So they will keep you 5 minutes and then tilt even more the table up to 60 °. In this position you will be 45 minutes. If you have any symptoms during that time (dizziness, nausea, blurred vision, etc.) you must communicate this. If at that time shown changes in the electrocardiogram or blood pressure test will end and will not be necessary to proceed to the next phase.
At the beginning of the second part of the test is injected through intravenous drug similar to the natural adrenaline in your body. The table again will tilt 60 ° and you will be so for 15 minutes. Normal is that notes that heart rate accelerates and you have palpitations in the chest. If you have any other symptoms you should contact, and any alteration in your cardiovascular constants if the test should be completed.
After this second part testing is complete and you can change your clothes, pick up your things and go home. Days later you will have an appointment with the cardiologist, who interpreted the results of the test and will inform you of the same.

Complications of the tilt table test

The more frequent the tilt table test complication is fainting. Ultimately, it is to reproduce the situations that cause fainting in the studied person. Other complications may include:
Nausea and vomiting.
Sustained hypotension.
Bradycardia maintained without recovery.
Myocardial infarction.
Tachycardia and other arrhythmias.
The personnel responsible for performing the test is ready to detect any of these problems and act accordingly. Do not forget that you are in a hospital you have the means to solve these problems.

Results of the test of the tilting table

Throughout the tilt table test different sensors capture the biological measures, which are stored in a register. At the same time that the test you can see these measurements, but it is difficult to analyze them because it takes time and dedication to study all the components at the same time.
You can go to pick up the results to the doctor who sent you the test, and that is usually a cardiologist or a neurologist. On that date it explain the alterations that have been throughout the study. The results may throw the following conclusions, roughly:
Instant blood pressure fall: usually happens in the context of orthostatic hypotension, i.e., by position, and not so much by heart failure.
Drop in blood pressure after a few minutes without changes in ECG: the main reason is vasovagal syncope, and the stimulus would be the position maintained.
Drop in blood pressure after a few minutes with changes in ECG: should study the electrocardiographic abnormalities and see if there is heart problems that justify the fainting.
In any of these situations, the doctor may recommend treatment. Can be simple recommendations (maintaining a good hydration), medications, or even a pacemaker placement.

What is the Fna (fine needle puncture aspiration)

Fna are some acronyms that refer to the Fine needle puncture aspiration, a test in which a sample of tissue is obtained puncionando it with a needle fine, but wide enough as to make cells, or even small pieces of material bodies will aspire. It is a simple test that allows the cell study of mass and nodules whose origin is unknown or doubt of whether they are benign or malignant.
PAAF first held in 1981 in New York (USA). The medical team that made her studying diagnostic methods minimally invasive that avoid perform biopsies open through conventional surgery. Thanks to the development of the FNAP have avoided thousands of surgeries in the world, and the complications of infections, necrosis or scarring injuries has declined precipitously.
The test can get two kinds of material: pieces of tissue or cells. When cells are obtained only a cytological study is possible. The pathologist (which specializes in the microscopic evaluation of tissues) can tell if obtained cells are benign, malignant, or describe alterations, but cannot define if it's a tumor or its degree of malignancy.
When pieces of tissue are obtained can be a histological study. In this case Yes you can see what kind of cancer are and what is the degree of malignancy. Sometimes refers to BAG (thick needle biopsy) when the material obtained is large enough.

When doing a Fna

The Fna or fine needle aspiration is a test that is performed when the following alterations in a person:
Thyroid nodule: before a nodule in the thyroid gland that does not capture iodine on a scan or does not produce thyroid hormone, a Fna should be done to rule out malignancy.
Breast nodule: when it is a recent appearance in a breast nodule felt should be a Fna. In young women most of the time will be benign fibroids that have no importance. If the nodule is not palpable, and only has detected by mammogram this test may not be carried out and will have to perform a biopsy with a Harpoon.
Adenopathy: lymph nodes are called to the lymph nodes that are swollen or enlarged. Occur most frequently in the neck, armpits, or English primarily, although they can appear anywhere on the body. When duran enlarged more than 2 - 4 weeks with no identifiable cause should study by PAAF.
Skin growths: when it appears a nodule or a lump in the skin without any reason their cells using Fna can study. Sometimes decides to perform a skin biopsy directly if it is superficial.
Study of internal organs: some organs which are within us not you can study directly with a needle blind. In such cases used computed tomography (CT) as a guide. Thus studies of the pancreas, kidney, unknown masses can be...
Samples of liver and lung: although they are internal organs is not necessary to use TC as a guide because its size and location allowed puncturing them directly through the skin.

Preparation for the Fna

If you will perform (FNAB) fine needle aspiration cytology these are the issues that you must take into account:
Duration: the test will last a total of 15 to 20 minutes. The biopsy itself will be one minute, the rest consists of the preparation of the material and the biopsy area.
Income: PAAF can be a query or a room of cures, in such a way that it does not require hospital admission. If you are entered they made you the FNAP in the same bedroom whenever possible.
Is necessary to be accompanied?: there is no why he accompanied, but yes it is recommended, as there are sensitive people who are sore or something queasy after the test.
Drugs: don't need to take any prior medication. Must be communicated to the doctor all the medicines taken regularly, and will decide if we will suspend any. Ibuprofenos, aspirin and other anti-inflammatory drugs should be avoided one week before the test. It may be necessary to suspend blood thinners such as warfarin or acenocoumarol the drugs. It is important to also inform of allergies to medications or other products, if you have them. Sometimes the doctor will prescribe you an antibiotic to take a few hours before the test and thus prevent the emergence of possible infections.
Food: should remain in fasting 8 hours before the test. If it is in the morning simply that not you breakfast or drink anything before the FNAP.
Clothes: you can perform the test with the same clothes every day. When you get to the hospital or doctor can give you a gown to change you should see fit, although often is enough to discover the part of the body that is going to puncture it.
Documents: it is important to bring with you the steering wheel which shows the performance of this test. The health insurance card is recommended. Normally you will not you any document after the test because it takes time to analyze the results.
Pregnancy and breast-feeding: the FNAB is not contraindicated in pregnancy or lactation, but that State should be aware that some organs studied will be altered from itself during these stages.
Contraindications: the masses that may not be felt can be a limitation for the test, unless they are in the abdomen or chest and it can guide the puncture with the TC.

How the Fna

First your doctor will assess in a consultation if necessary or not to perform (FNAB) fine needle aspiration. If deemed necessary will inform you of why it thinks, how it's performed, what information we can provide, and what are the possible risks. It will give you an informed consent document summarizing the main characteristics and you will have to sign it if you agree with its realization.
PAAF may make you it that day, but the most common is that you cited in another time. It is common to perform a blood test prior to put you to the test with an included study of coagulation. When they go it to ask you first of all that you change your clothes and views a comfortable gown for you and for the pathologist. You have to keep in mind is a minimally invasive and not particularly painful, so it is not necessary that monitor you vital signs (blood pressure, heart rate, etc.) thoroughly.
Sometimes they will offer you some relaxing drug to make you stay sedated during the test; It is recommended if you are nervous or are particularly sensitive to pain. Once you are ready ask you you to tumbes on a stretcher in a position that facilitates the realization of the test. If the Fna in thyroid ask you stay seated.
To proceed to biopsy the first thing that will is clean the skin in the area where it is made with alcohol or iodine compounds. So remove any contaminants germs from the skin surface. Then they inject an anesthetic and deeper levels from the skin surface. You will feel a slight prick of the needle, and then a burning sensation at the very moment in which penetrates the anesthesia. So that part of the body will be asleep and insensitive. Then they entered a long, hollow needle to reach the nodule to study. Through this needle is introduced another fine that will be sucked to get loose cells, and then catch a small cylinder of tissue if necessary.
Once the FNAP be removed the needles. It is normal that the puncture point blood a little; apply pressure continued for a few minutes to stop the bleeding. Then they placed a bandage or a compression dressing and you'll be ready to go home. It will not need to wait on the results, since they need to be processed for a time, and at first glance not seen any alteration. The bandage must hold for at least two days, and it is normal that the days after the test have manipulated pain in the area and need to take some pain reliever you your doctor will prescribe.

Complications of PAAF

All tissue sample outlets have risks to dealing with evidence that invade the body organs, albeit slightly.
The complications of the Fnac or fine-needle aspiration cytology tend to be rare and in most cases have a easy solution. They can appear during or after the test, and whenever they arise you should go to the emergency room.
Some of the most common complications associated with PAAF are:
Local infection with fever, swelling and heat.
Bleeding from the point of biopsy.
Uncontrollable pain.
Reaction to anesthesia during the test.
Pneumothorax (at the Fnac of lung).
Perforation of other organs (very unlikely).
Local spread of a tumor (unlikely).

The FNAB results

The results of the Fnac or puncture fine needle aspiration may take from one week up to a month. The waiting time, it therefore tends to be long, and requires patience and tranquility. The reason is that the aspirate sample can not be analyzed at the time. The following analysis will be carried out on this sample:
Cytological study: are the cells one by one and in small clusters. Their nuclei, which may be signs of malignancy can be studied as well.
Histological staining: using special dyes cells are colored and can be observed under the microscope directly. The most widely used staining is hematoxylin-eosin.
Immunofluorescence studies: you can attach fluorescent substances to certain components of the cells and thus verify its existence.
Microbiological cultures: If infection is suspected sample can be grown in appropriate media that allow the growth of microorganisms. It is a common in the lymph nodes that are suspected secondary to tuberculosis.
Molecular studies: specific proteins that classified the types of cells that contain the sample can be identified.
All of these tests will be performed by the physician. Along with the symptoms, analytical studies and the FNAP, specialist can make a diagnosis most of the times. So you can explain what happens to you, and what are the treatments available to solve your disease.

What is PCR (polymerase chain reaction)

PCR is an acronym that is known to the polymerase chain reaction (English Polymerase Chain Reaction), an advanced scientific technique which was invented by the American biochemist Kary Mullis in 1985. This technique allows to amplify small specific regions of DNA in the laboratory. I.e., get a small segment of DNA that would go unnoticed in any analysis is multiplied millions of times and is thus easy to detect.
Thanks to this technique have been able to be genetic studies in any field of science. For example, used daily for the identification of dead bodies or in the study of crime scenes to look for traces of the culprit. Also used in biology, to identify genetic chain of plants, animals or, above all, microorganisms. In medicine meets the experience of all those camps and is mainly used to identify aggressors germs found in our body.
When the PCR test was developed for the first time was a rather cumbersome and expensive technique to perform, but soon their use became widespread, and began to develop simple and very cheap computers that are used still today in many diagnostic centers.
Also, are designed more specific PCR can be chosen depending on the sample to study. The different types of PCR, in addition to the Basic, are:
Nested PCR: get amplify minimum samples of DNA to billions of fragments. It is therefore capable of detecting tiny strokes.
PCR in situ: allows the detection of DNA in the same place of the exhibition, without having to process it first with laboratory techniques. It is typically used for biopsies or cell.
Multiple PCR: this type of PCR are available to detect multiple traces of DNA at the same time and with a single sample.
With reverse transcriptase PCR: in this case, chains of RNA are used to detect DNA moulds. Transcriptase enzyme used reverse, the same used by HIV among other viruses.
Quantitative PCR or real-time PCR: added a fluorescent component that allows to measure light. More light, more quantity detected DNA.

When a PCR is made

It is recommended to perform a PCR in all situations in which you want to detect DNA chains and amplify it, either to perform studies on it or to identify their exact sequence. As for example, in the following:
Microbiological diagnosis: the most reliable method to identify a germ is isolated in a microbiological culture, but sometimes it is not possible to carry it out, either because the method of cultivation is difficult or because it is too expensive. In those cases the PCR can detect genetic material of the micro-organism that is necessary to detect. The sample collection can be of any type:
· Blood.
· Swab exudate.
· Vaginal exudate.
· Rectal exudate or stools.
· Urethral discharge or urine.
· Biopsy (skin, bone marrow, liver, etc).
· Sputum.
Detection of genetic mutations: genetic diseases are caused by a focal mutation in a specific region of DNA. It is very difficult to study them directly, so you opt for first multiply all the DNA sample and conducting studies with more broad-based. Thus confirms the diagnosis of many diseases like cystic fibrosis, the Chorea Huntington, Rendu-Osler-Weber disease, etc.
Studies of legal medicine: its use is widespread in this field and has many applications. The most common are the identification of corpses, the study of evidence from scenes of crime, investigation of cases of sexual abuse, paternity studies, etc. All of them are based on the amplification of DNA to study their sequence with ease.
Reviews of HIV or viral hepatitis: HIV and hepatitis B and C viruses are constantly in the blood of infected people. Your levels should periodically be reviewed to know the severity of the disease and the detection of DNA with PCR.a is used to do this

Preparation for PCR

If they are going to conduct a study with PCR these are the issues you should keep in mind to go well prepared to test:
Duration: sample collection usually takes very little time, what it takes to be a blood analysis. It usually takes seconds or minutes. The results are slow quite a bit, usually several days.
Admission: admission is never needed. Sample collection you do at the time. Also may be the case that made you the test during an entry to identify the cause of your illness, but in this case the reason for the income will be your state of health.
Is necessary to be accompanied?: no, just received a puncture when blood sample which must be, and is not usually very painful. You can go to the clinic, only walking or driving, and return the same way.
Drugs: don't need to take any prior medication. You should tell your doctor all medications you are taking at that time. Some medications can give false negative results of the test, for example if you take antibiotics and want to detect the germ that causes infection.
Food: you can eat normally, you don't have to go on fasting. But if the sample is blood is common to seize the prick of Analytics to measure yourself with other parameters in blood (sugar, cholesterol, etc.), so the best thing is you reports or directly stay in fasting if analytics is early.
Clothes: you can wear normal street clothes.
Documents: it is recommended to carry your health card, though most of the times is sufficient that you carry the wheel with which the doctor sent you proof.
Pregnancy and lactation: this test can be normally in either of the two situations. In fact, it is a test that is usually performed in periodic inspections of pregnancy established.
Contraindications: there are no contraindications. Just have to assess if it is really worth the test, and if the results would serve something.

How a PCR

When you get to the consultation the doctor will make you some general questions about your state of health: important diseases, risk factors, lifestyle, symptoms of infection, etc. The doctor will ask the PCR assay where deemed necessary and is the best diagnostic weapon to study your disease. After perform you a general physical examination, and assess if you can receive a mobile treatment or prefer that you stay logged.
After this first visit, they will take you the sample on which the PCR will be held. According to the site's collection of taking one or other measures are recommended. For example, if urethral should not urinate in the two hours before; If it is a best sputum that is first thing in the morning; and if it is better blood that matches a fever peak. But will those details you know the doctor before testing you, so you should not worry. If they are studying genetic disease usually they will make you a skin biopsy.
Once have collected you the sample to study you can lead a normal life. While waiting the results you must not be nervous and you must keep your routine. The study of PCR is performed in the laboratory, and you won't be aware of none of the steps of the technique. So that you know them, we summarize them here:
1. is extracted from the sample collected DNA that contains. This includes your own body cells, but also material of any germ that has.
2. the sample is heated up to nearly 100 ° C so that the two strands of DNA are separated.
3. added to sample a choke; This is a sequence of DNA synthesized in the own laboratory which is attached to a known DNA. For example, if we want to detect Cytomegalovirus we will use a specific Primer for it.
4. the sample is cooled so that the choke is a DNA studied. He then starts an enzyme called DNA-polymerase, which doubles the DNA to study.
5. repeat all the previous steps; whenever you finish a cycle will provide a duplication of the previous strands of DNA.
6. with the already amplified DNA genetic studies of quickly and easily can be.

Complications of the PCR

Complications of the PCR are virtually non-existent. It is a safe test that does not entail risks for persons who are subjected to it. The only risk is to accept false as positive or negative results, and take wrong steps in this regard. The sample does not usually entail risks, except those of the biopsies as the organ which will take.

Results of the PCR

The PCR results They may take several weeks since the sample is collected for study. To pick them up there to keep another appointment, since the documentation alone can not be interpreted by the patient. In consultation the doctor will be the most appropriate interpretation of the result. If you are admitted shall communicate them yourself during your stay in the hospital, or later if given medical discharge earlier.
The PCR is expressed in numeric values, but there is no standard limits for all studies. Each goal has own values, so that a PCR for Cytomegalovirus of 100 does not have the same value that a PCR of Chlamydia from 100.
The result of the PCR usually can be summarized in positive or negative. I.e. the DNA that we expected, or not found. That is essential in order to identify specific germs and provide a specific antibiotic, or to diagnose a genetic disease and measure the amount of mutated DNA.
Although it is a very effective test can provide false positives. It must be borne in mind that the choke can adhere to the DNA that we want to detect, but also joined by pure chance other strands of DNA that are close. False negatives are rare, since narrowly DNA that is usually detected.

What is polysomnography / sleep study

Polysomnography, also called 'sleep study', is a test used to diagnose sleep disorders. It was developed in the first half of the 20th century, thanks to the discoveries of Berger on the electric record of brain waves during sleep and wakefulness. Gradually identified normal patterns that exist in terms of health, and so we could relate electrical alterations with diseases.
However, its main use today is the study of the syndrome of obstructive Apnea of the dream (OSA), in which decreases in the percentage of oxygen in blood again and again throughout the night by the airway obstruction occur.
During a sleep study, various types of sensors that record biological constants are used. The determinations that will capture most are:
Brain electrical waves.
Blood oxygen level.
Heart rate.
Respiratory rate.
Movements of the eyes.
Movements of the legs.
Body position.
Snoring and any other noise you make while you sleep.
With these elements the doctor will be able to identify the different parts of the dream and its two main components, REM sleep and non-REM sleep.
The sleep study or polysomnogram is a test expensive and difficult to interpret, so must be carried out by experts and only when you go to be useful to determine a diagnosis or adjust a treatment. It is usually done in specific units of the dream that exist in hospitals and clinics. These units resemble hotel rooms where the person who undergoes the test will happen overnight while sleeping that explores its activity during sleep.
Although a few years ago the sleep studies were not performed very often, today it is a test that gets underway routine in many hospitals, even in children. There is also a type of home-based polysomnography, which you can do at home, but it is less reliable.

When doing a sleep study

It is a test that is useful when the following diseases are suspected, polysomnography and sleep study therefore serves to confirm your diagnosis:
Obstructive Sleep Apnea (OSA) syndrome: the most frequent symptom is falling asleep during the day. Snoring or feel poorly rested during the night are also symptoms to take into account.
Restless legs syndrome: Although much still does not apply this test for diagnosis, it begins to be useful to confirm this syndrome so difficult to control.
Narcolepsy: it is a disease in which people suffering from it come suddenly during REM sleep, even being awake during the day. The brain alterations that produce it can be studied during the dream with this test.
Sleepwalking: although it is commonplace among the population, in some cases can be a significant risk for the person and for your night's rest.
Disturbances of the heartbeat at night: there are arrhythmias that occur more frequently during the night and you can examine whether there is a relationship with the nocturnal oxygen levels in blood.

Preparation for polysomnography

If you are performing a polysomnography these are the issues that you must take into account:
Duration: polysomnography lasts all night. To be held during sleep it does not a waste of time very important to the person making it. The only extra time would be the preparation and collection after the test, which in any case would be less than an hour.
Income: polysomnography can be outpatients at home or in a hospital with a unit of the dream. The doctor will decide what make first.
Is necessary to be accompanied?: it is not necessary to be accompanied, just keep in mind that when it is done in the hospital you must spend the night there. The next day you can go back home or go to work directly. If the test is going to make any of your children, one parent must stay the night with him.
Drugs: don't need to take any prior medication. Should be communicated to the doctor all the medicines taken regularly and will decide which suspend or maintain, especially if you take drugs for epilepsy, muscle relaxing, antiarrhythmic, or psychiatric diseases.
Food: it is not necessary to remain in fasting prior to testing or after. A light dinner is recommended to sleep at ease and avoid taking all day coffee, alcohol and other substances that is exciting.
Clothes: you can go to the quote from the test with the same clothes every day. You can take your pyjamas, although they sometimes prefer to use a hospital Pajamas to make it easier to put the sensors on the skin. Don't forget to bring comfortable shoes and toothbrush. It is normal to not let you take a shower in the Center where the test, so better go to she showered with clean hair (you take shellac, gel or other hair products). If you're a woman you're not made-up, and if you are a man it is better you shaved the sensors stick well on the skin.
Documents: is essential to bring with you the steering wheel which shows the performance of this test. He is recommended to take the national document of identity and medical history on diseases to study, if you have them, although the doctor will already have it with him. Normally you will not you any document after the test because it takes time to analyze them.
Pregnancy and breast-feeding: polysomnography is not contraindicated in pregnancy or lactation, although it is not a test that is performed much in these situations since the biological constants that are studied are altered for itself during these stages.
Contraindications: do not have any specific contraindication.

How polysomnography

First, the doctor will assess whether it may be useful to perform polysomnography, and will see if it is better to perform directly in the hospital or outpatients at your home. Ambulatory polysomnography is less reliable than the polysomnography of the hospital, because all the constants that we cannot be measured. However, it is very useful to rule out diseases and so only test the hospital people who already show alterations in the ambulatory sleep study.
One will quote you a night for the study of sleep and they explain the basic measures that you need to know to submit yourself to it. The day of the test must be a normal life, avoiding to take a NAP after lunch to get to sleep that night. Best thing is that you get to hospital an hour before the start of the test, to take time to familiarize yourself with the room where you will spend the night. Avoid do any stressful activity evening before you go to make the sleep study.
When you are comfortable and with the Pajamas they placed a series of sensors in the skin of the chest, arms, legs and head. Also a small clip on one of the fingers of the hand. Then you will see that all sensors work and properly capture measures to study.
Once all the sensors don't have to sleep immediately. They will tell you that you can be in the room reading or watching TV awhile until you feel sleep. Is normal for that night you are more nervous than usual, you sleep in a place you do not know, but the best thing is to relax and try to get to sleep.
Overnight you will not notice of absolutely nothing. You'll sleep like you any day. The next morning you will wake up at the agreed time and will help you to remove all sensors with acetone, diluting the glue. Then you can change your clothes and collect your stuff without having to wait for any results.

Complications of polysomnography

Polysomnography is a completely safe test, which does not represent any risk for people who perform it. The only complication that is known of her is that some of the sensors that are stuck to the skin can irritate it in especially sensitive people, something not very common.

Results of polysomnography

During the night the different sensors capture biological measurements stored in a register. At the same time performed polysomnography or sleep study, these measurements can be observed, but it is virtually impossible to analyze them because it takes time and dedication to study all the components at the same time.
Normally during the night, there is only a technician next to the room that is performed, which is sufficient for testing. The days after a doctor will examine the record and will see what changes there are, so will decide a diagnosis and propose solutions to the person who has been subjected to the test.
You can go and pick up the results of polysomnography medical specialist that you commissioned the test, is usually an pulmonologist or a neurologist. On that date it explain the alterations that have been throughout the sleep study. It can be observed that the main problem lies in breathing pattern and the amount of oxygen reaching the body, or that alterations are found in the nervous system affecting sleep directly. As a result of the results the doctor indicate possible solutions to your problem, if it exists.

What is a study of evoked potentials

The study of evoked potentials is a test that is used to study the brain electrical activity from external stimuli. Each of these stimuli is collected by a different sensory organ, which are translated into electrical impulses that travel through the neurons to specific areas of the brain where they are interpreted. This study records the electrical activity through a series of surface electrodes that pick up electrical impulses and extend them to study them. It is therefore a very similar to electroencephalogram test.
Thanks to these studies it is possible to identify neurological lesions in almost any area of the nervous system; In addition, they are particularly useful in patients who, for various reasons, can not express if you are able to notice external stimuli.
Evoked potentials studies are divided according to the sensory organ that is studied. The main ones are:
Study of Visual evoked potentials: studies the brain reception of Visual stimuli. To do so are asked to the person subjected to the study to look at a screen showing a flashing white light.
Study of somatosensory evoked potential: explores the brain receiving tactile stimuli. This placed a series of electrodes on the skin areas that want to study and apply mild electric shocks.
Study of auditory evoked potentials: explores the brain receiving auditory stimuli. This produced a series of clicks and treble tones that are audible to the human ear.
The doctor who analyzes such tests is the neurophysiologist or neurologist. The study is usually performed on units specific Neuropsychological what's in hospitals and clinics, and with the input data will be an analysis of the origin of the neurological alterations that the patient has. It is not a very expensive test, but their interpretation is difficult, and must always be accompanied by a good full medical study using clinical interview and physical examination.

When doing a study of evoked potentials

Evoked potentials studies are useful when the following diseases are suspected:
Screening of deafness in infants: with these studies can be checked that a newborn receives auditory stimuli in the brain, discarding so you have a damage in the ear.
Identification of neural lesions: almost any disruption in the nerve pathways could be detected using this type of studies. It is often used for this reason in the diagnosis of multiple sclerosis, polytraumatized or spinal cord paralysis, among other disorders.
Discard simulations or psychiatric pathology: there are certain situations in which neurological symptoms are simulated voluntarily or in the context of a psychiatric disorder. The study of evoked potentials is a completely objective test that detects if really electrical signals reach the brain.
Diagnostic tumor acoustic nerve neurinoma: this type of tumor appears in the nerves that transmit nerve impulses from the ear to the brain. It causes deafness and can be detected through these studies.
Study of the patient in a coma: when a person is in a coma, it is difficult to tell which areas of the brain are danadoas. Evoked potentials identify brain areas that have no activity despite the external stimuli.
Study of blindness: evoked potentials can be noted if the nerve injury that prevents the vision is found in the retina and the optic nerve, or if you are in the cerebral cortex responsible for receiving electrical signals.

Preparation for the study of evoked potentials

If they are going to carry out a study of evoked potentials , these are issues that you must take into account:
Duration: the study of evoked potentials lasts 1-2 hours, although much of this time is dedicated to the preparation and collection of the necessary material.
Income: this study can be performed in a hospital with a unit of neurophysiology, without the need for income. After the test you will be able to make your normal life. They recommend you have slept little last night, except if it is a test of Visual evoked potentials, in which case you should arrive well rested.
Is necessary to be accompanied?: is not necessary to be accompanied.
Drugs: don't need to take any prior medication. Must be communicated to the doctor all the medicines taken regularly, and will decide which suspend or maintain, especially if you take drugs for epilepsy, muscle relaxing, antiarrhythmic, or psychiatric diseases.
Food: no need to remain in fasting prior to testing or after.
Clothes: you can go to the quote from the test with the same clothes every day; Perhaps they will call you discover you the part of the body to study. Avoid creams and products of personal hygiene in the area of the body to study. You should also avoid wear masks or lacquers in the hair.
Documents: it is important to take with you the steering wheel which shows the performance of this test. You have to carry the health insurance card and medical history on diseases to study, if you have them, although the doctor will already have it with him. It can give you a document after the test.
Pregnancy and breast-feeding: evoked potentials studies are not contraindicated in pregnancy or lactation.
Contraindications: may be a type of study that are contraindicated in patients with epilepsy because certain (especially Visual) stimuli can trigger a crisis. Not tend to make tactile stimuli to persons with myopathies or other diseases of the muscles, by the risk of that sustained spasms.

How the study of evoked potentials

To make a study of evoked potentials, first the doctor will assess if it is useful for the diagnosis. If you see fit, I will quote you one day for the test and you will explain the basic measures that you need to know to submit yourself to it. Avoid drinks with caffeine (coffee, Coca Cola, energy drinks, etc.) the day before the test, and you don't put creams or lotions the day of the test in the area of the body that go you to study, nor lacquer, masks or hair gel on the hair. If it's a Visual evoked potentials test ask you that you rest well in house to be awake and alert for the next day, but for the rest they will ask you you to stay within hours, because thus you'll be more drowsy and it will be easier to perform the test.
When you arrive at the hospital and passes to the test room ask you to lean on a bed or a comfortable armchair. If it is necessary to ask you that you discover the part of your body to study. They cleaned the surface of the skin and hair with antiseptic products to remove germs and remove surface fat. The electrodes placed them you glued to the skin with a gel; also use a gel on the scalp, but the electrodes are usually put assemblies in a CAP to make installation easier. If it's a somatosensory study may put you electrodes on legs, arms and back.
The number of electrodes is highly variable, depending on the neurological study alteration, sensory organ affected, and extension of the study. It varies from a couple of electrodes to more than twenty. All electrodes have a cable that terminates in an oscilloscope that records all the electrical signals.
Once placed all electrodes is to stimulate in various ways, depending on the sensory to study organ. If it is a study of Visual potentials you'll see repeated flashes of light, moving chess boards, and other forms of light. If it is an aural study you will hear clicks and treble repeatedly. If it is a somatosensory study, you will notice small little annoying, electrical discharges in areas of skin that have to study. During that time the technician who is performing the test will give you simple commands, like that you close your eyes or you breathe deeply.
Once the test completes one electrode will be one. You should be cleaned again the area to remove the gel, but then at home you will have to clean you better and wash your hair. You can then make your daily normal activities, although keep in mind that your hair can offer an aspect of poor hygiene.

Complications of the study of evoked potentials

The study of evoked potentials is a very little invasive test and does not usually pose any risk for people who perform it. Some complications have been described is that some of the electrodes can irritate skin in especially sensitive people, something very rare.
The study of Visual evoked potentials should be performed with caution in people who have suffered previous seizures.

Results of the study of evoked potentials

Throughout the study of evoked potentials the different electrodes pick up electrical signals, which are stored in a digital memory. At the same time that the test you can see these measurements, but it is virtually impossible to analyze them because it takes time and dedication to study different records at the same time.
The neurophysiologist will analyze the registry of nerve impulses that have been detected in each of the studied nerve regions. A series of waves, which are altered according to the intensity and duration of the neuronal signals shall be respected in each record. They must study carefully to verify that indeed the electrical alterations are due to external sensory stimuli.
You can go to collect the results to the doctor who sent you the test, and which will normally be a neurologist or ENT. In that quote professional explain the alterations that have been throughout the study. It may necessary to perform more tests requiring more diagnosis, such as a CT scan or an MRI. It will explain the various treatment options in your case, and will recommend you the most appropriate.

What is the Prick test: allergy skin tests

Skin prick test or allergy tests are tests which are made on the skin in order to identify the substance that can trigger an allergic reaction in the patient. This is inserted into the skin a tiny amount of the possible causative agent of allergy. We call this substance that triggers an allergy allergen. When the allergen triggers a reaction in the skin is considered that the individual is allergic to that substance.
In general there are two systems for diagnosis of allergic diseases. On the one hand they are laboratory methods measuring different substances originating from the allergen, as for example a few antibodies called IgE that are specific to the different substances that cause the problem (mites of dust, milk, fish, etc) in the blood. On the other hand are tests in vivo, of which there are three variants:
Immediate hypersensitivity skin tests, also known as skin puncture or prick test tests.
Delayed hypersensitivity allergic tests, also called patch tests, patch or patch test testing.
Provocation tests, which consist of managing allergen controlled by nasal, bronchial, conjunctival, orally or parenterally. The most common is the bronchial provocation test for the diagnosis of some respiratory allergen-induced asthma.
In this chapter we will focus us in allergy skin tests known as the prick test or patch test.
Of puncture or prick test skin tests are considered the method most appropriate for the diagnosis of allergy to inhalants for their safety and reliability. It consists of the application of different allergens in the forearm or back. The intensity of the reaction allows you to discover the cause of the allergy and the magnitude of it. Allows us to study a possible allergy to drugs (such as antibiotics, anesthetics...), to pollens, epithelia of cat and dog, mites, fungi, plant and animal foods, latex, insect (mosquito, cockroach), fabrics (cotton), and other many substances.
The patch testing or the patch tests are tests that are performed to identify mainly substances which cause of contact allergy or allergic dermatitis. It consists of a small disc which contains the allergen and that sticks to the back of the patient. They are useful for example in eczema by make-up, or allergies by jewelry or different metals.

Allergy test prep

These are the issues you should keep in mind when you go to a test of allergy or prick test:
Duration: the test of the prick test is performed in a few minutes. The possible skin reaction is examined after 15 minutes. The patch test is also performed in a few minutes, but the skin reaction is examined at 48 hours, so you have to go twice to the query.
Entry: the test can be done on an outpatient basis, but I should occur a reaction very serious, which is exceptional, the patient can be entered.
Is necessary to be accompanied?: do not need to be accompanied.
Drugs: is not necessary to take any prior medication. It is very important to not take antihistamines or corticosteroids prior to the test, as they may reduce allergic reactions and distort the results. The doctor will tell you with how long in advance should discontinue this medication.
Food: in general, it is necessary to go on fasting.
Clothing: you can wear any clothes you want, but it is important that you can easily discover the arms or shoulders, depending on where you place the allergen.
Documents: should be informed consent, which is a role where they explain you what is the test and its potential risks. You should read it carefully and take it signed. You must take the wheel of the test request.
Contraindications: It should not be to test for allergies in the following cases:
  • Taking medications such as steroids or antihistamines that can interfere with the results.
  • Skin lesions that hinder the interpretation of results.
  • Severe or unstable patients that may worsen when the test gives an important adverse reaction.
  • The pregnancy.
Pregnancy and lactation: these tests should be avoided during pregnancy because of the risk of serious reactions that may damage the fetus from occurring. In addition, immunity is altered in pregnancy and the results may not be conclusive. However, it is generally considered that allergy tests can be made during breastfeeding, as the substances used are not going to reach the infant.

Other considerations

It is very important to not take antihistamines or corticosteroids prior to the test, as they may reduce allergic reactions and distort the results.

Allergy test is performed

Allergy tests are usually made in a service of Allergology. The prick test technique is done in a single visit to the query. Initially inform you about the technique that will be performed and possible skin reactions which may appear as a small papule or itching at the puncture points.
Cleaned you with alcohol the area chosen for the test, which can be the inner side of the forearm or back. Once evaporated alcohol, you will receive on the skin a drop with a summary of the substance being studied. Usually different extracts, are tested by what are several separate droplets about 2 cm each other. The technician who carried out the test will catch a small Lancet and with it cross the drop at a 45 ° angle. It slightly prick skin doing a very superficial puncture and trying to not make blood. Prick rise minimally skin to put there a small fraction of the allergen. Used a different Lancet for each extract to study. Then puncture with a small adjacent signal points are marked and the remains of the droplets are cleaned.
They will tell you to wait between 10 and 20 minutes, usually 15 minutes, to proceed to read the results of the test, i.e., to examine the possible skin reaction that may have occurred. It is very important that don't scratch the test area during this time to not mask results. The reactions that may occur after that time, when the patient has already abandoned the inquiry, are not taken into account.

How is the test of the patch or patch test

To carry out the test of the patch or patch test must go twice to the query. We will inform you the technique that you will perform. You will be back a few small discs impregnated with a small amount of the substance or substances will be assessed. These small discs are placed in two rows and remain 48hrs. Passes those hours must return to the query to read the results, i.e., to evaluate the skin reaction that it has been able to produce.
During these 48 hours need to follow some tips to not alter the results: you should not get wet back, avoid the heat, sweating, and sudden exercises that can remove tape, no scratching or expose to light the area, not to take drugs that distort the results such as corticosteroids or antihistamines. Finally, if patches begin to fall off, we will fix them with a small adhesive bandage to prevent possible reactions to the tape that distort the results.
Skin allergy techniques are very safe testing. In very rare cases can occur potentially serious reactions with the prick test in patients especially sensitive to any allergen. Allergy symptoms can range from a feeling of heat and the appearance of a skin rash, to a very severe allergic reaction called anaphylactic shock. There will always be a team ready to solve these rare eventualities. Allergy is often immediately after administration of the allergen. However, very rarely, you may receive allergy hours after contrast administration, causing itching, difficulty swallowing or breathing. In such a case you should urgently contact a doctor.

Allergy test results

Tests for allergy or prick test results are read within 15 minutes of puncture evaluating the size of possible papules and reddened area (erythema) which have been formed.
There are several ways to adjust the result, and one of them is as follows:
When there is no erythema or papule, or there are less than 1 mm Erythema is classified as.
The absence of papule or the presence of a very light papule with one rash of no more than 3 mm in diameter, is classified as a +.
A papule of up to 3mm or Erythema not exceeding 5 mm in diameter is classified as ++.
A papule 3 to 5 mm in diameter with Erythema is classified as a +++.
Any major reaction is classified as a +++.
There are some errors in the test which can distort the results, for example:
Put too much together extracts (less than 2 cm apart) so that the reactions together and prevent their visual separation.
Make a puncture which penetrates form under the skin. This originates a false-negative result, i.e., a test that is actually positive gives negative.
Use too much of the substance to study, so that it can spread and mix with other extracts.
Bleeding occur with puncture. This can result in a false positive result, i.e. the substance produces an irritation that is diagnosed as allergies, when in fact there is no allergy to the allergen.
Have taken antihistamines prior to the testing. This can result in a false-negative result.
Propagation of allergens in the time of the test or to remove the allergen solution. It can result in a false positive result.

The patch test results

Patch tests results are read 48 hours after the placement of the patch. The classification may be in the following way.
When there is no reaction is classified as.
When there is a pale erythema or doubtful reaction is classified as?
When there is a slight Erythema is classified as +.
The presence of a papule with erythema, edema and vesicles is classified as ++.
The presence of a papule with edema, large or grouped vesicles, or a very strong reaction, is classified as a +++.
Also a false-negative result can be when placed bad patch, read the reaction within 48 hours, or taken any medication that reduces allergic reactions, such as corticosteroids. On the other hand, there are various circumstances that can lead to a false positive for example if it is placed the patch on an already irritated area or if there is a reaction, not the allergen tested, but the patch adhesive tape.
The doctor will give you the results via a report written in a few days. The result report will include data on the technique used, tested allergens and the reaction obtained with each of them. The doctor will indicate the need for any treatment or other complementary explorations.

What is the breath test

The breath test is a medical test that is done to patients suspected of suffering from an infection by a bacteria called Helicobacter pylori. This bacterium is found in the walls of the stomach, and survive in an acid environment thanks to an enzyme called urease. This enzyme manages to convert urea into commodities that react with acid and maintain a microenvironment with a pH that is suitable for the survival of the H. pylori.
The implication of this bacterium in various gastric pathologies was not discovered until the last years of the 20th century, so treatments and the available evidence did not exist until a few years ago. Thanks to its discovery has been to treat serious diseases such as the ulcer of stomach with just a simple medical treatment with antibiotics, thus avoiding complex surgeries.
One of the methods to check if the H. pylori colonizes the stomach or not is the breath test. It consists of taking a certain dose of urea in capsule form, and after a specific time, measure urea exhaled breath. The amount of exhaled urea directly depends on the presence of H. pylori in the stomach.
There are other tests to diagnose infection by H. pylori. Some of them are carrying out serology on an analysis of blood, stool examination or biopsy by endoscopy. However, the breath test is the most effective and the easiest to perform, both the doctor and patient.

When a breath test is done

It is recommended to perform a breath test to everyone where it is necessary to find out if they have an infection by Helicobacter pylori to treat their symptoms, or to prevent their occurrence in the future. The most common situations in which testing is used are as follows:
Active duodenal ulcer or gastric ulcer: this type of ulcers are injured in the wall of the stomach or duodenum that bleed and can drill into the digestive tube. There are many factors that favor it (tobacco, alcohol, anti-inflammatory, etc), but are directly related to the presence of Helicobacter pylori many of them. If the bacteria is detected it can be eliminated with a medical treatment and that solves the ulcer, which heals by itself.
Last gastric or duodenal ulcer: as we have said previously, the discovery of the relationship between the Helicobacter pylori and digestive diseases did not happen until a few years ago. It is not uncommon to find people who had an ulcer and received a different treatment (surgery in many cases). It is recommended to test these people and to eliminate the bacteria, if found; thus diminishes the risk of relapses of the disease.
After receiving treatment against H. pylori: when a person is detected Helicobacter pylori should be treated to eradicate it for awhile. Then you should be back to the breath test to check that the bacterium has been removed. If not, need to try with other antibiotics because it can that the first were not effective.
Dyspepsia: named to all symptoms of poor digestion (heaviness in the stomach, belching, heartburn and reflux, etc). Often they are caused by gastritis, or alterations in the secretion of gastric juices. The Elimination of the Helicobacter pylori may improve symptoms.
Prior to treatment with anti-inflammatory drugs: If a person takes some anti-inflammatory in a timely manner (such as ibuprofen or others) is not necessary to perform any previous test. But if treatment with anti-inflammatory steroids will not be very long breath test must be performed to detect the bacteria and eliminate it; so will decrease the risk of ulcers.

A breath test preparation

If they are going to perform a breath test and you want to go well prepared the day of the appointment, these are the issues that you must provide for:
Duration: usually lasts half an hour since you arrive to the clinic until you leave. Time that must wait since tomas urea until it is measured in breath are 10 minutes.
Admission: admission is never needed. It is a test that can be done at a time.
Is necessary to be accompanied?: not, is a painless and not invasive, so you can only attend the clinic and return in the same way.
Drugs: don't need to take any prior medication. You should tell the doctor all medications that you are taking at that time. Two weeks prior to the test you can not take any antibiotic, drugs that contain bismuth, or inhibitors of pump of protons (like the pantoprazole or omeprazole).
Food: you have to go to the test in fasting. If it is done in the afternoon, you can not have eaten in the 6-8 hours before.
Clothes: you can wear normal street clothes, does not affect the test.
Documents: must not carry any type of document, only your personal identification and your health insurance card, which is always best to take with you when you go to medical testing.
Pregnancy and breast-feeding: is a test that can be performed in either of the two situations without problem, although you must tell your doctor that you have knowledge of this.
Contraindications: no contraindication.

How a breath test

When you get to the consultation of the gastroenterologist will make you some general questions about your state of health: important diseases, risk factors, lifestyle, place of work, etc. You will also ask for digestive symptoms such as heartburn, the stomach pain, vomiting, bleeding... After perform you a general physical examination and request the breath test if it considers that it is worth making it.
The day of the test you will have to come to the fasting. Usually take advantage of this day to get blood and make you new analysis. You will then be asked to take a glass of water with a small capsule of urea. The amount of urea that tomas is minimal, and is also a substance that is in your body in a natural way, so you should not worry. The urea will be marked with carbon 14, so when it reacts with enzymes of the Helicobacter pylori it will be released and can be measured in the breath.
When you've taken the pill you have to wait seated and quiet. After 10 minutes you will be asked you exhales breath through a small tube. It is a test similar to the test of breathalyzer that are made when you drive a car. Your breath is collected in a balloon and it is analyzed to quantify the amount of carbon-14 that is dissolved in the air. The analysis can be immediate or be later, depends on the laboratory and the technology available.

Complications of breath test

Complications of the breath test are not known. It is a completely safe test that does not entail risks for persons who are subjected to it. A possible complication associated with testing is offering a falsely negative, this often happens when taken antibiotics or drugs not permitted prior to the test. Thus, an infected person will be undetected and not receive treatment. Falsely positive results are less frequent.

The breath test results

The breath test results They should be interpreted by a gastroenterologist that you assess measures to take if it is a positive result. When it is positive the doctor will prescribe you three drugs that eliminate the Helicobacter pylori stomach. These drugs are accompanied by two antibiotics omeprazole (usually amoxicilna and clarithromycin, but there are many more options). After a few weeks you will again repeat the test to check that all is well.
When the result is negative it is possible to have the bacteria colonizing the stomach. The doctor not may prescribe you any medicine against this microorganism because you would not serve anything. If they have done you the test because you had symptoms of indigestion the doctor will pose different tests that try to discover why show these symptoms.
Something to keep in mind is test may give a false negative result and really does have the Helicobacter pylori in your stomach. If your doctor thinks that's your case can repeat the test once, and this time must take extra care prior (such as medication and fasting). This situation is quite uncommon, because the test gives very successful results.

What is a pulse oximetry

Pulse oximetry is a diagnostic test which is used constantly in hospitals and medical emergencies. With it we can know how much oxygen there is in the blood without performing an extraction of blood, unlike what happens in the arterial blood gases.
Oxygen passes into the blood through the alveoli of the lung and is transported within red blood cells, hemoglobin-joined. Hemoglobin is a protein with a molecule of iron, which is where the oxygen attaches, and when that happens the proteins change shape. Pulse oximetry takes advantage of this feature to measure the blood oxygen.
The device that is used is a Pulse Oximeter, a small clip that is placed on the tip of any finger of hand. At one end it has a light and transmitter in the receiver front end. Light through the finger and is altered with oxygenated hemoglobin, in such a way that there are many more molecules of hemoglobin occupied with oxygen over the beam of light is altered.
Alterations of the beam of light is collected by the receiver of the Pulse Oximeter, there are interpreted, and give a numeric value that represents the percentage of oxygen in the blood. The ordeal a few moments, does not represent any discomfort to the patient, and can help to initiate treatment or perform other tests quickly.

When a pulse oximetry is made

Pulse oximetry is a test that is used every day in medicine of patients admitted, in emergency situations, or in outpatient consultations. It does not imply any invasion for the patient and can bring much useful information. It is the first step to testing more annoying as an arterial gas. The situation where the gases is an important utility is respiratory failure.
Although respiratory failure can only be diagnosed through an arterial blood gases, pulse oximetry allows you to decide the realization of this technique. If pulse oximetry is normal, not worth a gas analysis, and the patient saves is a blood collection something annoying. Respiratory failure situations can be diverse, some of them would be asthma, COPD, pulmonary fibrosis, acute Lung edema, etc.
Other metabolic alterations such as acidosis, alkalosis, or problems such as hyperventilation and renal failure, cannot diagnose is via pulse oximetry. In these cases is you must perform an arterial blood gas that allows not only know the levels of oxygen in blood, but also the levels of ions in blood and carbon dioxide.
An exception would be carbon monoxide poisoning, a very toxic molecule that forms in combustion of low quality (homemade bonfires, stove, living room, etc.), and which binds to hemoglobin disabling it. In that case the blood gases would oxygen levels in normal blood, but pulse oximetry would detect this abnormality in hemoglobin, being the only way to diagnose it.

Preparation for a pulse oximetry

If you will perform a pulse oximetry , these are the issues that you must take into account:
Duration: lasts very little. The time that passed since you put the Pulse Oximeter in any finger until the results is just a few moments.
Admission: admission is not needed. It can be in a hospital or an outpatient, even in the House. Some people with chronic neumologicos problems have their own Pulse Oximeter at home and use it on a daily basis.
Is it necessary to be accompanied?: no.
Drugs: don't need to take any prior medication. You should tell your doctor all medications are taken at the time, although they do not usually affect the amount of oxygen in the blood.
Food: is a test that is not altered by eating in the hours before, so it is not necessary to save fast.
Clothes: you don't need special clothes. The Pulse Oximeter is placed on a finger and do not need to undress so they put it.
Documents: it is advisable to carry your health card, but at the time of you pulse oximetry not usually ask you for any identification.
Pregnancy and breast-feeding: the test can be taken without modifying any attitude. It is better to let the doctor know that you're pregnant, because pulse oximetry may be slightly different.
Contraindications: there are no contraindications.

How a pulse oximetry

Arriving to the inquiry or to the emergency room doctor will make you some general questions about your state of health (important diseases, risk factors, lifestyle, work place...), and above all insist the symptoms that have led you to consult. The symptom that is associated with respiratory failure is shortness of breath, fatigue , or shortness of breath.
After perform you a general physical examination, and assess the realization of a pulse oximetry if it believes it may be useful for diagnosis and treatment. To be a simple test is usually done on all persons directly.
At the same time, a doctor or a nurse will proceed to put the Pulse Oximeter. Is usually placed on the fingers of the hand; somebody is invalid. But there are situations in which the blood does not well to the tip of your fingers. Some of them are physiological, as exposure to the cold, and others are pathological situations, such as sepsis, Raynaud's disease, etc. In those cases, you can try placing the Pulse Oximeter in other locations, such as for example the earlobe.
Few second after placing the Pulse Oximeter will begin to detect the blood pulse, then light will cross the finger and deform according to the hemoglobin molecules that are occupied with oxygen. A number, that the doctor be construed to take clinical attitudes according to the result appears on the display of the Pulse Oximeter.

Complications of pulse oximetry

There are no complications when performing the pulse oximetry. What if there are complicated situations in which this technique cannot be used. Some of them are sepsis, cardiogenic shock, arterial ischaemia, Raynaud's disease, freezing or cryoglobulinemia. All of them have one factor in common: decrease or absence of blood flow to the extremities.

Results of pulse oximetry

Pulse oximetry results consist of a percentage representing the amount of oxygen in the blood attached to hemoglobin; It is what is known as saturation of oxygen (SatO2). This information can also be obtained with a gas analysis, but pulse oximetry allows to obtain it directly, without estimates.
Oxygen saturation is not the established method for diagnosing respiratory failure, only the partial pressure of oxygen (pO2) is the valid data for this purpose, and it can only be obtained through an arterial blood gas. However, oxygen saturation has a very strong correlation.
Levels of between 98 and 100% oxygen saturation are considered normal. With age, it is usual that the passage of oxygen is not optimal, so it also can be accepted as normal up to 95%. In chronic pulmonary patients to 90% can be considered normal. The reason for considering 95% as the limit of normalcy is that it corresponds with a partial pressure of oxygen of 60 mmHg, limit to diagnose respiratory failure.
If a pulse oximetry is normal the doctor will take care of other problems, but if it is less than 95% it will be his priority. It will first ask an arterial blood gas, to confirm the data and observe exactly the level of oxygen in the blood and other metabolic disorders. Then you put oxygen through nasal glasses or mask, depending on the seriousness of the situation.


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