During a skin test, a drop of a suspected allergen is pricked on the surface of the skin. The test is performed on the forearm. Many suspected allergens are tested at the same time with allergens specific to Louisiana(Southeastern region of the United States). If you are allergic to one of the tests, you will have redness and swelling at the test spot within 15 minutes. The size of the reaction is measured and indicates your degree of allergy.
Unfortunately, medications may interfere with skin tests and some patients may not be able to undergo a skin test. As a result, blood tests are then utilized because medicine does not interfere with the results. However, the results are not immediate and depending on the test, there can be false positives.
The test results alone do not diagnose allergies. All test results, from either type of test, must be interpreted together with your medical history and physical exam.