Is One Allergy Test Better Than Another?
Is one allergy test better than another?
Well, yes and no. Both skin prick tests and blood tests look for the presence of an IgE allergy antibody. Both of these tests are reliable when used in the context of a proper clinical history. So, the best test is really the story that you provide to your allergist. We want to know things like what symptoms you have. Are those symptoms reproducible upon exposure to your suspected trigger or allergen? Are those symptoms consistent with what we would determine to be an allergic reaction? If the clinical history suggests that you do have allergies, then skin testing and blood testing are both reliable to help confirm the presence of allergies or rule out allergies, when we don't suspect that allergies are the cause.
Now, these tests have limitations. Both skin tests and blood tests have high rates of false positive results. So we really want to pick and choose what things we test for very carefully based upon the history. Neither skin tests or blood tests were ever designed to be used as screening tests. We can't just test for everything and kind of see what comes back and then diagnose allergy by that. Neither skin test nor blood test can predict the severity of future reactions. They can only be used to determine the likelihood that allergy is present.
But we do have a gold standard test when people have concerns about food allergy. So if you really have concerns about food allergy and your testing is indeterminant, the oral food challenge is the gold standard. It's a very safe way to learn more about how your body's immune system responds to a food. You eat gradually increasing amounts of that food under supervision. If no symptoms occur after eating a set amount of food, then you're not allergic to that food because allergies cause an immune response. Therefore, every time you're exposed to that, you should have reproducible symptoms.
So it's really important to understand how tests are best utilized. But most importantly, we always start with the best test available, which is you. What's your story? What's your clinical history?
David Stukus, MD, is a Professor of Clinical Pediatrics in the Division of Allergy and Immunology, Director of the Food Allergy Treatment Center, and Associate Director of the Pediatric Allergy and Immunology Fellowship Program at Nationwide Children’s Hospital and The Ohio State University College of Medicine. He is board certified in allergy/immunology and pediatrics.
Dr. Stukus has devoted his career to communicating evidence-based medicine and best clinical practice to colleagues, medical professionals of all backgrounds, patients, and the general public. In addition to providing clinical care for children with all types of allergic conditions, he participates in clinical research, quality improvement, patient advocacy, and medical education.
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