Tuesday, September 9, 2008

Allergy Testing Methods

By Dorothy Medlum


Do you have an allergy, but are unsure of the specific allergen causing your allergic reaction? Your doctor may be able to recommend a variety of allergy testing to diagnose your condition.

Different types of allergy testing can be used to identify various allergens. Some tests work better than others, depending on the allergy suspected. Therefore; be familiar with the various allergy tests available prior to making an appointment with your doctor. The tests available may fall into several categories including: Scratch tests, elimination tests, and blood tests.

Scratch Tests

The scratch tests are the most common of the allergy tests that are done. This test consists of placing a small amount of the suspected allergen onto the surface of the patient's skin, and then making a scratch or prick to allow the substance to penetrate the skin. The site is then observed closely for indication of an allergic reaction.

Swelling, redness, or itching are signs that an allergic reaction has occurred. A result can often be detected in as little as twenty minutes using this type of testing. The other advantage to this kind of test is that many different allergens can be tested together. This makes this method especially useful if the allergen is unknown, airborne, or a food allergy.

Elimination Diets

The elimination diet is an allergy test done when the allergy suspected is a food allergy. In this testing, a variety of foods that are potential allergens are eliminated from the diet for a period of several weeks. Each food is then gradually added back to determine which selection will cause the allergic reactions.

Each food is then introduced gradually back into the person's diet, carefully monitoring to determine which selections cause the allergy symptoms to return. This method works best on mild allergic reactions, but can also be potentially dangerous for severe allergies. If a severe allergy is suspected, a third method of allergy testing is preferred to ensure a life-threatening substance not enter into the system in any way.

Blood Tests

A RAST, or radioallergosorbent test, is the final type of allergy testing that is commonly performed. This is achieved by using blood drawn from the patient. It is then examined for the presence of immunoglobulin (Ige) antibodies. This indicates whether the immune system is producing an allergic reaction to the body. These Ige's tell your doctor if you are allergic to certain allergens, although this testing does not tend to be as accurate and precise as other methods used.

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