Soon, simple test to detect peanut allergy

TORONTO - Scientists from University of Manchester in Britain are testing a new diagnostic tool that may help predict life-threatening peanut allergy.

Lead researcher Adnan Custovic suggests that testing for a molecular component of the peanut called Ara h 2 is an excellent predictor of true peanut allergy.

He said the test was able to identify 97 per cent of those at risk of anaphylaxis from exposure to peanuts.

That is significant discovery because it is notoriously difficult to identify the children at real risk.

For example, in the new study, about one in 10 children had a positive skin or blood test that indicated a peanut allergy, but when they underwent an oral peanut challenge, only one in 50 had a true peanut allergy.

“The lack of specificity of current tests when used in isolation indicates many patients will inappropriately be given the diagnosis,” Globe and Mail quoted Custovic as saying.

“The new diagnostic test, which accurately discriminates peanut allergy from tolerance, will mean we can target avoidance to those patients really at risk and remove the considerable stress that comes from the many false positive sensitivity tests,” he added.

Susan Waserman, an allergist at McMaster University in Hamilton, while the new research is intriguing it may not be ‘the magic bullet’.

She said the notion that an Ara h 2 test could definitely identify those at risk of an anaphylactic reaction to peanuts should be greeted with caution, particularly because the study involved only 19 children with severe peanut allergy.

“We don’t know yet if this is the magic bullet,” she said.

“But the good news is that we’re moving in the direction of much more specific diagnostic tests,” she added.

According to Waserman, if the new test, developed by Phadia AB, a company based in Uppsala, Sweden, works well it will not eliminate the need for an oral challenge, in which a person ingest peanuts in a clinical setting to determine if they have a severe reaction.

“That’s still the only way to figure out who’s truly allergic. I’m not sending my patients out into the world without it,” she added.

The study appears in the Journal of Allergy and Clinical Immunology. (ANI)