New test for peanut allergy more accurate, safe than current tests

May 3 (UPI) — A new blood test for peanut allergy diagnosis is 98 percent accurate, safe and comes at a low cost, according to researchers who developed it.

Researchers at the Medical Research Council in Britain developed the test, which is five times more cost efficient than the standard oral food allergy test. The research, which the scientists say can be adopted to other food allergies, was published Thursday in the Journal of Allergy and Clinical Immunology.

“The new test is specific in confirming the diagnosis so when it’s positive, we can be very sure it means allergy,” Dr Alexandra Santos, an MRC Clinician Scientist at King’s College London, said in a press release. “We would reduce by two-thirds the number of expensive, stressful oral food challenges conducted, as well as saving children from experiencing allergic reactions.”

Peanut allergy is the most common one for foods, ahead of milk and shellfish, and has a potentially fatal reaction.

About 3 million people in the United States report being allergic to peanuts, according to the American Academy of Allergy Asthma & Immunology.

To diagnose peanut allergy, medical personnel give legume substances to patients in incrementally larger doses, testing for a reaction. The method, however, carries a risk of severe, life-threatening allergic reaction, in addition to false-positive results.

“The current tests are not ideal,” Santos said. “If we relied on them alone, we’d be over diagnosing food allergies — only 22 percent of school-aged children in the U.K. with a positive test to peanuts are actually allergic when they’re fed the food in a monitored setting.”

The researchers developed a mast activation test, or MAT, which they said could act as a second tool when skin-prick test results are inconclusive, and before referring them to specialists for an oral food challenge.

The new test concentrates on mast cells, which help trigger allergic reactions. They recognize an antibody called immunoglobulin in plasma and, in allergic patients, produce biomarkers associated with allergic reactions.

The current skin-prick test and IgE test also measure the presence of IgE antibodies.

Reactions to the test include skin sensitivity, itching or constricting of the mouth, throat and airways, and digestive problems.

For the new test, researchers analyzed blood samples from 174 children participating in allergy testing — 73 had peanut allergic and 101 were peanut-tolerant. Not only was the test accurate, it reflected the severity of allergy for each patient. And this test, unlike the food challenge, doesn’t require an allergist or specialist nurses to monitor for adverse reactions and give necessary medical support.

The researchers say the test could also be used to monitor for allergic response during drug evaluation and clinical trials, though they are focused on other food allergies first.

“We are adapting this test to other foods, such as milk, eggs, sesame and tree nuts,” Santos said. “This test will be useful as we are seeing more and more children who have never been exposed to these foods because they have severe eczema or have siblings with allergies. Parents are often afraid to feed them a food that is known to cause allergic reactions.”