Allergy tests are simple, quick, and relatively painless. And they're the best way to confirm whether or not a particular allergen (or allergens) will cause a person to have an allergic reaction. Typically a person will suspect that he or she is allergic to something before taking an allergy test, so often an allergy test is performed as a way to confirm a suspicion. Skin tests and blood tests are the most common types of allergy tests performed today.

Once the problem-causing allergen is singled out, that person can then make the necessary modifications in his/her environment and/or lifestyle to protect against an allergic outbreak. This is important because allergic reactions can range from a simple irritating skin outbreak all the way to serious difficulty with breathing.

Skin Allergy Tests

In most situations, a skin test will be performed first as it usually results in reliable findings. Plus, skin tests for allergies are faster and less expensive than blood tests. With skin tests, several allergens can be tested simultaneously. The person administering the test begins by cleaning the test area, either the back or the arm, with alcohol. Next, a liquid form of the allergen is rubbed on the skin. If more than one allergen will be included in the test, each will be spread 1 – 2 inches apart. The location of each allergen likely will also be labeled.

Next either a needle (single prick) or an instrument with between 5 to 10 pricks on it is used to break the surface of the skin which causes the allergen solution to get into the skin. If a reaction is going to occur, a raised, red, blotchy mark will usually appear within 10 to 15 minutes. The medical term for this appearance is a wheal and its appearance means that the person has had a positive reaction to the allergen.

Sometimes if the test for an allergen is negative, another skin test called an intradermal test is performed. This is where the allergen is actually injected with a needle deep in the skin. Again, if a wheal develops, that is considered a positive reaction. A skin patch works off the same premise. A patch that is soaked with an allergen is applied to the skin for about 2 days. The problem with the patch is that it will come off in the water or sometimes from excessive sweat, so bathing and exercising are advised against while the allergy tests are in process.

Blood Allergy Tests

Blood tests require a sample of blood to be extracted from the person's vein. The collected blood gets sent to a laboratory where it is tested for the presence of allergen antibodies.

There is much debate as to whether or not one type of allergy test is better than another. When in doubt, as with any potential medical condition, it is always best to seek another opinion or get another test. A decision about treatment should be made only after discussing a person's test results and history of symptoms with a trained medical professional.