March 21, 2012
A New Option In Peanut Allergy Testing
Researchers from the University of Melbourne and Murdoch Childrens Research Institute have found a way to better test for peanut allergies. This new method has proven to not only be more accurate, but also more convenient and cost effective than current tests.
Parents who suspect that their child may be allergic to peanuts currently have three options for testing against this allergy: The first option is a blood test that measures the immune system´s response to peanuts. This requires a blood sample to be sent to a laboratory.
The second option is a skin prick test. By exposing the skin to small amount of proteins found in peanuts, doctors look for a small bump or hive to appear on the skin, thus revealing that a peanut allergy may be present. While this is the most popular way to detect the allergy, false positives can occur, as the test only reveals if the immune system responds, and not if the child is actually allergic.
The third and most dangerous option is a food challenge test. Conducted under a physician´s supervision, the child is then given a small amount of peanuts and then observed for any symptoms. The worst of these symptoms is anaphylactic shock.
The new test aims to not only increase efficiency and accuracy, but also to eliminate the dangerous food challenge test.
By isolating and using the peanut protein called “Arah2”, the researchers have developed a two-step blood test to accurately determine if a peanut allergy exists.
According to lead researcher Professor Katie Allen, PhD, the new two-step process first tests the blood for an allergy to the whole peanut protein. Then, it goes on to test for an allergy to Arah2.
The test is aimed at patients who have a family history of peanut allergies or who are otherwise at high-risk for the allergy. Such a test reduces the false positives from other blood tests, as well as prevents those without the allergy from avoiding peanuts for the rest of their lives. In their studies, they found that more than half of positive skin prick tests resulted in a false positive.
The institute´s researchers conducted the tests on a group of 5300 infants in metropolitan Melbourne, Australia.
Nearly 200 of those who had a confirmed peanut allergy were also accurately confirmed through the new two-step process.
Dr. Allen said in a press release “”We have people who have had a positive skin prick test who have never eaten a peanut and for 15 years may have been inadvertently avoiding a food they weren´t even allergic to.”
Armed with this new research, Dr. Allen hopes that physicians and clinics will be able to quickly diagnose a food allergy and relieve some of the stress placed on these clinics.
“Due to the rapid increase in rates of sensitization to foods, allergy services are overwhelmed, and food challenge tests might be difficult to access. This method would help alleviate the current strain and demand on clinical allergy services, with the allergy patient waiting times in excess of 18 months in many centers in Australia,” said Allen.
Rather than schedule an appointment with an allergy specialist, patients would simply need to schedule an appointment with a general physician.
The study is published in the Journal of Allergy and Clinical Immunology.