How A Skin Test And Blood Test Compare For Diagnosing Your Allergies
If you have allergies, your doctor may recommend you get tested to find out what triggers your symptoms. A skin prick test is one of the most common allergy tests, but there are certain situations where your doctor may recommend a blood test instead. Here is some information about how the skin test and blood test compare.
Results Are Immediate With A Skin Test
One advantage of a skin test is the results are immediate. You take the test in your doctor's office and wait several minutes to see if your skin reacts. You'll know the results of the test the same day. If you get a blood test instead, you'll need to wait several days to get the results because your blood sample will be sent to a laboratory that does allergy testing.
The Blood Test Might Be Safer
If you've had a serious allergic reaction in the past, your doctor may be reluctant to give you a skin test because you might have a serious allergic reaction to the test too. Even though you'll be in the doctor's office the entire time of testing so you can get immediate treatment if you have a reaction, it is safer to do a blood test instead because there is no risk of reaction at all with a blood test.
Also, if you have an allergic rash at the time of the test, it will be very difficult to obtain accurate results with a skin prick test. In that case, a blood test will be more reliable and it won't further irritate your skin.
Medications May Interfere With A Skin Test
If you take certain medications to control your allergy symptoms and your doctor doesn't think it's a good idea to stop them for a few days to do skin testing, then a blood test is a good alternative. If the medication prevents your symptoms from flaring, then your skin may not react to the skin test properly, but medications have no effect on the blood test. The blood test will still pick up on antibodies in your blood that signify an allergy.
Skin Tests Are More Sensitive
A skin prick test identifies the substances you are allergic to and is also able to reveal the degree of the allergy you have. For instance, you could have a mild rash or a more severe skin reaction. This lets the allergist know when you have a serious allergy that could be life-threatening. A blood test picks up on the antibodies from the allergen, but it doesn't indicate the degree of your potential allergic reaction.
One thing to note is that both types of tests can return false positive results. This means the tests may indicate you have an allergy to something you do not. On the other hand, there is rarely a false negative result. So, you don't have to worry about having an allergy to a substance and the tests not picking up on it.
Other things that may affect the type of test you have is if your insurance will pay for the blood test, whether or not you have very sensitive skin or eczema that will be irritated by the skin pricks, or if you have a serious medical problem and your doctor wants to stress you as little as possible. Your allergist has to take all these factors into consideration when determining which is the best type of allergy test to order. It's even possible your doctor will recommend both tests to get the most information about your allergy triggers.
For more information, contact local professionals like Southern Allergy and Asthma PC.