1 AnswerRealAge answered
A RAST (radioallergosorbent) blood test looks for specific immunoglobulin E (IgE) antibodies in your blood. If the antibodies are present, it most likely indicates a true allergic reaction. RAST is the safest type of allergy test, but compared with a skin prick test, it takes longer to produce results and it can't test for as many allergens at once.
This type of allergy test is typically used only in special circumstances where skin testing is not advised -- for example, if a person has a severe skin condition or is taking certain medications.
3 AnswersTracy Konoske , Nutrition & Dietetics, answered
I'd like to expand on what Jim White replied...It's important to determine if you have what is called "allergy" which is a Type 1 hypersensitivity reaction. It is IgE mediated and is immediate. These are not always life threatening but they could be. Think of things like peanuts, shellfish, etc.
Then, there are delayed reactions, which are called food sensitivities. They still involve the immune system, but they are not IgE mediated. They are Type 3 and/or Type 4 hypersensitivity reactions. Because they are delayed, dose dependent (not causing a reaction every single time) and person specific, they are hard to isolate. "Allergy" tests will not pick up a type 3 or type 4 reaction. Alcat and LEAP MRT both will - of the two, MRT has better technology at this point since it can quantify reactions. IgG tests cannot identify chemical triggers, and IgG has been shown to be protective as well as pathogenic.
Working with a dietitian experienced in this area is paramount. Food triggers can be hidden, and it will work best if the patient can avoid any and all reactive foods for 4-5 weeks while the immune system calms down. Education is needed to do meal planning, grocery shopping, label reading, what to do if a reaction occurs, etc.
There are many MRT therapist available, myself included. A doctor is needed to order the test if you wish to use insurance. For those without insurance or with poor insurance, a cash price is available and no doctor is required. Just a blood draw and a good attitude:)
1 AnswerDr. Paul M. Ehrlich, MD , Allergy & Immunology, answeredThe delayed hypersensitivity (TB or candida skin tests) test is a descendant of the old tine test, and utilizes either the familiar PPD tuberculin, or candida, mumps, or other substances that most people have been exposed to at one time in their lives. The process involves injecting a few drops under the skin, usually on the forearm. The physician observes the site in 72 hours for a reaction. In a normally functioning immune system, the candida or mumps sites should show a raised, red area. This test is also qualitative as it determines the function of the T cell or cell-mediated system.
1 AnswerDr. Christopher M. Webber, MD , Allergy & Immunology, answered on behalf of Sky Ridge Medical CenterThe three main causes of allergy symptoms are allergic rhinitis, irritant rhinitis or a combination of both (called mixed rhinitis). Allergic rhinitis is caused by a component of your immune system called the immunoglobin E (IgE) antibody. The cause of nonallergic rhinitis or irritant rhinitis s is a direct irritation of your nose. There is no way to tell them apart by just asking questions, not even for an allergist.
Allergy testing (either skin test or blood test) determines which of these is the underlying cause of your allergy symptoms. Allergic rhinitis is an immune system response that has positive allergy tests (either scratch test or blood test). Irritant rhinitis is a nonimmune response that has negative (normal) allergy tests.
It's important to know what causes your symptoms, because the right diagnosis will lead to the right treatment.
1 AnswerDr. Michael Roizen, MD , Internal Medicine, answered
If you already know what is causing your rash, say a new soap or the ring you bought on the street that contains nickel, you can do things to avoid it so your rash doesn’t come back. But for those who have no idea what’s causing their reaction, an allergist can perform a patch test to (hopefully) isolate the pesky allergen that is causing your discomfort. There are two techniques:
1) A drop of a liquid containing the suspected allergen is dropped onto the skin (usually on your arm or back, depends on how many you’re testing). Your doc will then prick the area. If the skin turns red and blotchy, that indicates the possible presence of an allergy. Possible is key here; skin tests do yield many false positives.
2) A small amount of the potential allergen is injected under the skin. If a lump appears at the site of the injection, you are judged to have tested positive. The bigger the lump, the stronger the liability.And don’t worry, these unpleasant red bumps aren’t permanent. They’ll heal and disappear about a week after the test. There is a controversy over how valid this type of testing is.
1 AnswerDr. Paul M. Ehrlich, MD , Allergy & Immunology, answeredScience shows us that skin tests and blood tests for allergies don't really measure the same things. The antibodies that register in a blood test have a half-life of two days. They come and go without putting your immune system on a state of red alert. The ones that react in the skin have a half-life of six to eight weeks, which means that your body is ready to strike for a protracted period.
1 AnswerRealAge answered
It's important to pinpoint exactly what's sparking your allergy symptoms in the first place. Even if you think you know, it's good to check again down the road because allergies to new substances can develop. Allergy testing from a board-certified allergist or immunologist should take place if you find your symptoms are not being adequately controlled. Allergy tests are practically painless, and because they're more accurate than they used to be, they may actually detect precisely what's causing your allergy symptoms, which in turn will help your doctor tailor an effective treatment plan that works for you. Simple tests like the skin-prick test can help uncover allergies to many common substances, including dust mites, pet dander, mold and pollen.
1 AnswerDr. Lawrence T. Chiaramonte, MD , Allergy & Immunology, answeredWhen I was training, I had a mentor named Alan Pearlman who told me, "I never test for allergies." I thought he was crazy. Well, if he was, then I am almost crazy, because I test less and less.
As you develop clinical experience, you find that a good history is much more important than any lab report. Sometimes I will test to confirm what I already suspect.
Patients and parents of patients don't always like this. They will say, "If you don't test, what am I paying you for?" I tell them, "You are paying me to use all my experience to make you (or your child) better."
2 AnswersReston Hospital Center answeredSkin allergies and their triggers are most commonly diagnosed through skin tests, including scratch tests, prick tests, and most commonly patch tests. Skin testing usually involves a doctor applying samples of allergens to a small area of skin, usually on the forearm, and then sometimes scratching or pricking the skin to let the allergen seep in. After some time, usually anywhere from 15 minutes to 96 hours, the doctor examines the skin to determine whether there was a reaction to the substance. If a person has certain skin conditions or is taking medications that would interfere with a skin test, a blood test that analyzes levels of antibodies may be done instead.