Skin Scratch Test

• The first type of skin allergy test is the skin scratch test. The test is usually performed when looking for many possible allergens. A small drop of the allergen is scratched on the skin. This is usually done on the back of the person being tested. If more than one allergen is being tested, the doctor will create a row of different allergen scratches that he has marked in order on a test paper. This way he can rate reactions to each substance. If the person is allergic to the allergen that was scratched into the skin, there will be a bump that occurs. The size of the bump then tells the doctor how severe the allergic reaction is. There will probably be no pain with this test. The test takes about 20 minutes to create a result.
  
  

Injection Skin Test

• The second type of allergy skin test is the injection skin test. A small amount of the possible allergen is injected under the skin. If more than one allergen is being skin tested, the doctor will again create a row of allergens. He will then mark it on a test sheet to monitor the reaction. This test is usually done on the upper arm. This test is mildy painful, at most. The reaction is also noted by how large the resulting bump is. This test also takes about 20 minutes to create a result.
  
  

Blood Test for Allergies: The Enzyme-linked Immunosorbent Assay

• The first type of blood test a doctor may order to detect for allergies is the enzyme-linked immunosorbent assay or ELISA or EIA for short. This test looks for antibodies that may result from an allergic reaction. These are called your immunoglobulin E, or IgE levels. The IgE levels are often elevated in a person who has allergic reactions to certain substances. This test is performed like a typical blood draw where blood is collected from a vein into a tube. Results take about a week for the doctor to receive.
  
  

Blood Test for Allergies: Radioallergosorbent testing (RAST)

• The second type of blood test for allergies is called the radioallergosorbent testing or RAST for short. This test is often used when food allergies are severe or are suspected. Blood is drawn from the patient and then the allergen is injected into a sample of the blood. The lab technician or doctor will look at the blood under a microscope to see how much immunoglobulin results from the allergen. It is much safer because the reaction of course does not take place within the body but in the blood sample. This is the ideal test for patients who might have had a severe allergic reactions in the past. The results take about a week for this test also.
  
  

Deciding Which Test to Have

• The final decision as to which test should be performed to check for allergies will lie with the doctor. The doctor will take a look at the medical history, past allergic reactions, types of reactions and will decide which test is needed. After getting the results, the doctor can then decide on the best course of treatment for the allergies.