Information On Allergy Testing Procedure

Submitted by Medical Health Test Team on October 16, 2012

An allergy is an abnormal reaction of the human immune system. An allergy occurs when the immune system perceives a substance to be harmful to the body and attacks the area that is exposed to the substance. Allergic reactions usually involve skin related symptoms such as rashes. They may also result in inflammation. An allergic reaction could be triggered by exposure of the skin to an allergen. It could also be triggered by consuming the allergen through the mouth or breathing it in through the nose and mouth. The reaction is a result of the attack by the body’s immune system on the area that has been exposed to the allergen. While the actual allergen has caused no damage to the body, the allergic reaction may result in a serious medical emergency. This is the case especially when the allergen affects the throat as any inflammation there can lead to asphyxiation. Therefore, a person who suspects an allergy should be tested for that allergy in advance. This allows for precautionary medication to be carried in case of an allergic attack.

Allergy testing is broadly divided into two types of tests. One is on the subject itself while the other is in a laboratory. The subject based test is known as a skin prick test. In this test, a small amount of the allergen is injected just under the skin of an individual and the area it has been injected into is marked or circled. If the person is allergic to the substance injected, then a reaction should be seen in the surface of the skin, usually in the form of a mild rash or a bump in the skin. Reaction time and intensity varies with different allergens as well as with the intensity of the response of the individual. The skin prick test may be uncomfortable for an individual. It may also be dangerous if not properly administered, leading to a more serious allergic reaction. Furthermore, a person’s skin may already be covered in a rash if they are suffering from an allergy at that time. Finally, only a single allergen can be tested using a single test. These are all limiting factors when it comes to the applicability of this test.

The other type of testing is a laboratory based blood test. Here a blood sample is drawn and this sample is tested using the RAST procedure which is the Radio Allergosorbent Test. This test can be used for multiple allergens on a single sample and is safer, but more time consuming.

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