If a person is feeling like they have allergies, they may need to have an allergy test to figure out where the problem is coming from.  Allergy testing will involve having skin or blood tests done to determine what substance or allergen is bringing on the problem.  Skin tests are the most common because they are fast, reliable, and much less expensive than blood tests.  However, any one of them can be used.

If you do not have any idea what you may be allergic to, allergy testing can be very time consuming. Your doctor would start with the obvious and work toward the rare. The more you can tell your doctor about the circumstances surrounding your suspected allergic reaction, the quicker He or She can diagnose your allergy.

A small amount of a suspected allergy-causing item can be placed on or below the skin to see if a reaction starts.  There are three types of skin tests that can be performed to determine the problem.  It will be up to the person and the doctor to decide what is going to be the best route in finding the culprit. 

A skin prick test is done by using a drop of solution containing a possible allergen on the skin and a series of scratches or needle pricks that allow the solution to enter the skin.  If the skin develops a red or raised itchy area, it is going to mean that the person is allergic to the allergen.  This is called a positive reaction. 

Putting a small amount of allergen solution into the skin does an Intradermal test.  An intradermal allergy test may be done when a substance does not cause a reaction in the skin prick test but is still thought of as an allergen for the patient.  This is going to be the more sensitive test than others and is often found to be positive in people that do not have symptoms to the allergy. 

A skin patch test is something that is placed on a pad and is taped to the skin for 24 to 72 hours. This test is used to find a skin allergy called contact dermatitis. In addition, a blood test can be performed on a patient.  Allergy blood tests are going to look for things in the blood that are called antibodies.  Blood tests are not always as sensitive as skin tests but are most often used for people that are not able to have the skin test performed on them.

The most common type of blood test is called radioallergosorbent testing or RAST. It is used to determine the blood level of a type of antibody that the blood may produce in response to a particular allergen.  IGE levels are often higher in those that have allergies or an asthma problem.  RAST may be used for people who cannot have skin tests like those that are taking different medications like antidepressants because this will make the tests less accurate. 

There are other lab testing methods like the immunosassay capture test and it may be used by your health care professional to find out more information on what is causing your allergy problems.  Again, it is all up to the patient and the doctor to determine what types of testing are going to be used to find the real reason behind the allergy.