Blood and prick tests not foolproof allergy tests
Skin-prick and blood tests should not be used as the sole means of diagnosing allergies in children because that can lead to unnecessary avoidance of environmental exposures or food, according to allergists from Johns Hopkins Children’s Center in Baltimore and Mount Sinai Hospital in New York. A real culprit also could be missed.
The allergists say in an article published in January’s issue of Pediatrics that the tests should only be used to confirm suspicions based on symptoms and medical history. They should not be used to look for allergies.
In the case of a suspected food allergy, the children should undergo a food challenge, where they consume a small dose of the allergen under medical supervision.
The problem is that skin and blood tests detect antibodies from the immune system released in response to allergens, but not actual allergic reactions. That means they only detect sensitivity and can’t tell if there will be a reaction or how bad a reaction would be.
“Allergy tests can help a clinician in making a diagnosis but tests by themselves are not diagnostic magic bullets or foolproof predictors of clinical disease,” said Dr. Robert A. Wood, a Hopkins professor of pediatrics, in a statement. “Many children with positive tests results do not have allergic symptoms and some children with negative test results have allergies.”