Different types of allergy tests for asthma
Allergy Skin tests for asthma
If you get asthma from allergy then your body will secrete this particular immunoglobulin E. The allergen reacts with this IgE and results in an allergic reaction which further inflames the airways.
The following 3 types of allergy test are performed on your skin with this regard:
The most common allergy test is a patch test. Not only for asthma, but a patch test is recommended before using cosmetics as well. In this test, the suspected allergen is applied over a patch, which will be applied over a specific area of your skin for 48 hours. You need to carefully observe for any kind of allergic response like redness and itchiness over skin. The patch test is not always accurate and therefore you have to undergo the following test.
Skin Prick Test
In this test, a tiny amount of suspected allergen will be placed in forearm and your skin will be pricked gently with a needle through the particle. This allows the allergen to come in contact with your skin. You have to wait for 15-20 minutes then to observe the possibility of the reaction. Your skin would turn red, bumpy and itchy if you are allergic to that substance.
The test involves injection of a small amount of the suspected allergen underneath your skin. That particular area of the skin is observed after 20 minutes. A typical allergic reaction i.e. small hive with swelling and redness would occur at the site if you are allergic to that foreign particle injected intra-dermal. It’s important to note that intra-dermal test is usually not recommended for food or latex allergy as the test is very sensitive. The results are also more consistent than skin prick test.
Allergy Blood test for asthma
The principle of allergy blood testing for asthma is similar to that of skin tests, i.e. your blood is tested for IgE load and for specific allergens. Allergy blood test might or might not be combined with skin test.
The following 2 types of tests are performed:
Radioallergosorbent Test (RAST)
RAST detects allergen specific IgE in the blood. They are used on a person who cannot undergo skin prick tests, for example in case of eczema. Blood is drawn out from a vein preferably from inside the elbow or surface of the hand and is then sent to the laboratory to conduct the allergy testing. It could be used to dust mite, food allergy, pet dander, etc.
Quantitative Immunoglobulin Determination Test
Quantitative immunoglobulin testing is not diagnostic allergic test for asthma, but it is a strong indicator of how your immune system is responding to the reaction. The blood test is performed to determine the load of the major immunoglobulins i.e. IgG, IgA, and IgM. The test might or might not be ordered in case of asthma.
Written by: healthplus24.com team
Date last updated: July 18, 2014