09 May Skin Test vs. Blood Test: Which Test is Better?
Have you ever had a blood test or skin test? It’s the peak of allergy season, and allergens are everywhere. This is the time of the year that you see your symptoms worsen. They may even get so bad that you need to see a doctor.
Allergy specialists use testing to determine the environmental factors or foods a patient is allergic to. Typically, allergists use a skin test or a blood test as their diagnostic procedure, leaving many patients wondering which type of testing is better. The short answer is each test has its own advantages and limitations.
How are Blood Tests and Skin Tests Similar?
Both blood and skin tests work to diagnose allergens by detecting antibodies known as Immunoglobulin E (IgE). IgE’s live in a patient’s blood and skin, recognize allergens, and trigger an allergic response, allowing the physician to determine what factors make the patient’s symptoms flare up. Blood tests detect IgE in the blood, while skin tests detect IgE on the skin.
Advantages of Skin Tests
Generally speaking, skin tests are more sensitive than blood tests, meaning they are more likely to detect allergies that a blood test may miss. Skin tests also require less wait time, as results are typically delivered in 15-20 minutes, rather than the one to two-week wait time of blood tests. Skin testing also allows physicians to select a broader range of allergens. For example, at McGovern Allergy and Asthma Clinic, physicians can access over 150 different environmental and food allergens, allowing them to test for uncommon types of allergies. Blood tests are limited by what allergens laboratories test for—which is usually a much smaller amount than skin tests. Lastly, skin testing is much less expensive than a blood test.
Advantages of a Blood Test Versus a Skin Test
While skin testing may seem like the way to go, there are advantages to blood testing that skin testing cannot provide. Skin tests require patients to stop taking antihistamines five to seven days before examination. This is because anti-histamine medications make skin less reactive. Blood tests, however, are not affected by drugs. Patients with severe allergies who cannot stop taking medication can benefit from continuing their medication while undergoing a blood test. Patients with sensitive skin (dermatographia) or hives can produce false positive results on a skin test, reducing the test’s reliability.
Furthermore, patients with eczema or severe allergic reactions are also better candidates for a blood test verses a skin test. Lastly, blood testing allows for component testing in food allergies, meaning the test can actually determine the exact proteins in food that a patient is allergic to, and can even predict the severity of his or her allergic reaction.
Which is Better, a Skin Test or a Blood Test?
There is no one-size-fits-all allergy test. Your best bet to getting the most out of your skin test or blood test for allergies is to consult an experienced allergist, like those at McGovern Allergy and Asthma Clinic. A knowledgeable and professional allergist will determine which type of testing is best for each patient—taking into consideration his or her previous medical history and the advantages and limitations of each type of test. Sometimes, allergists may even use both types of testing when results from a blood or skin test aren’t definitively clear.
If you are experiencing allergy symptoms and want a skin test or blood test, contact the experienced team at McGovern Allergy and Asthma Clinic today. Call 713-661-1444 or go to Mcgovernallergy.com to book an appointment today.