What happens when you get an allergy test?

Question

My doctor told me that I should have an allergy test done. I have had a friend have an allergy test done and she had a bunch of bumps on her arm. My doctor said it was just a simple blood test. Has the test changed? What should I expect? Is it painful?

Answer 1

There are many methods of allergy testing. Among the more common are the skin tests, elimination-type tests, and the radioallergosorbent test (RAST).

Skin tests are the most common. Specific methods vary. The scratch test (one of the most common methods) involves placement of a small amount of suspected allergy-causing substances (allergens) on the skin (usually the forearm, upper arm, or the back), and then scratching or pricking the skin so that the allergen is introduced under the skin surface. The skin is observed closely for signs of a reaction, usually swelling and redness of the site -- a controlled hive with so-called wheal and flare. Results are usually obtained within about 20 minutes, and several suspected allergens can be tested at the same time.

A similar method involves injection of a small amount of allergen under the surface of the skin (intradermal) and watching for a reaction at the site. Skin tests are most useful for respiratory allergies (in which the allergen is inhaled), a penicillin allergy, insect bite allergies, and food testing.

Food allergies are usually tested by using various elimination diets -- the suspected foods are eliminated from the diet for several weeks and then gradually re-introduced one at a time while the person is observed for signs of an allergic reaction. Because a person might believe he or she is allergic to a certain food, a double-blind test may be advised to find out if this is true. In a double-blind test, suspected foods and placebos (harmless substances) are given in a disguised form. The person being tested and the provider are both unaware of whether the substance tested in that session is the placebo or the food substance. A third party knows the identity of the substances and identifies them with some sort of code. This test requires several sessions if more than one substance is under investigation.

While this strategy is useful and practical for mild allergic reactions, it must be undertaken carefully in individuals with suspected severe reactions to foods. In this instance, blood tests may be a safer first approach, as described below. Of note, skin testing is almost never performed to detect food allergies for the same reason of the higher risk of causing a severe allergic reaction.

The RAST is a laboratory test performed on blood (see venipuncture ). It tests for the amount of specific IgE antibodies in the blood, which are present if there is a true allergic reaction.

Other tests include immunoglobulin measurements (see serum immunoglobulin electrophoresis) and the blood cell differential or absolute eosinophil count (increased eosinophils can indicate the presence of allergy). Provocation (challenge) testing includes exposure to the suspected allergen -- for example, in the diet or by inhaling the suspected allergen -- under controlled circumstances. This type of test may provoke severe allergic reactions. Challenge testing should only be done by a doctor.

Answer 2

If your just getting a simple blood test, then that's it. It's just a blood test. You've had those before I'm sure.
I got the other type where you lay on your back and they test your skin to see if you are allergic to what they poke you with. That doesn't hurt at all. I was really nervous, but I didn't feel anything. I think the needles they use aren't very big they're like tiny pin pricks. It was more annoying than painful. I remember it was a little itchy too. Your friend probably had the bumps due to the allergic reaction it caused in her skin, not the needles. The bumps don't hurt either, they go away. I guess theres more than one type of test or they updated it or something. Either way, I wouldn't be worried - Its not painful, and if it is, it's very, very minimal. If you're having more doubts why not talk to your friend? I think you'll do great, Good luck!

Answer 3

It isnt too painful, I was raelly scared when I got it done when I was thirteen. You go to a room for testing and they sit you down on a "bar like" table. You put your arm out, and they then apply different solutions to your arm that can make it have an allergic reaction. Im not sure on why or if it is before or after they apply the solutions, but they do prick your arm for each solution applyed. The prick is barely even a scrape, and if your eyes were closed, you probably wouldnt even want to say OUCH. My eyes were open, and it didnt hurt. Its a very easy thing to get done, and it is good for letting you know what is up with your allergies.

Answer 4

When I was about 10 I had an allergy test done and it was not a blood test but I wish it was. I'm not trying to like scare you or anything, and it could of just been that I was young and I thought it was bad. But they took this long thing about the size and shape of a chalkboard eraser and pressed it on my arm. It had these little prickly things sticking out and stuff on them. My arm then got all these itcy bumps on them if I where allergic to what was put on the thing. It was pretty painful, espically when my arm started to itch from what I was allergic from.

Sorry for my totally great medical terminology. haha

Answer 5

I've never heard it referred to as "a simple blood test". What I experienced was that a friendly nurse sat me down with a lot of little bottles of clear fluids. Each bottle contained a small dose of something a person might be allergic to (cat dander, dust, mold, etc.) The nurse poked me with a small amount of each of these fluids, making a pattern on my arm. We then waited. Whichever fluid created a redness or swelling on my arm was something I was allergic too. Most of the things had no reaction, but a few did have a reaction. The bumps itched a little bit, but they werent severe and didn't last long. I didn't think it was painful, and I learned what I was allergic to; cats, dust, mold, etc. This information is helpful to me now, several years later, because it lets me know what to avoid in my daily life so that I dont walk around feeling like I have a cold all the time.

Answer 6

there are two ways (at least) to do allergy testing... the older way involves making tiny pricks on your back and arm and putting a solution of the allergen in them and see how much of a welt they made.....

there is also a simple blood test where they draw blood from your arm...it doesn't hurt very much and you get results from the lab.....

Answer 7

Usually it unvolves a series of pin pricks that get introduced to different things you might be allergic to, that's why you get the bumps.

Answer 8

nothing dangerous is going to happen all ull have after the test is a little irritation for a day or two.

Answer 9

Yes

Answer 10

What they do is to scratch you with allegens, to see if you react to it. They may use your arm, or back, or whatever other area of the body they choose.