Blood check to revolutionise peanut allergy tests

A NEW peanut allergy test could prevent thousands of people needlessly worrying about eating the snack.

Currently, skin-prick testing, which involves placing a small amount of the peanut protein on the flesh and looking for an immune reaction in the blood, results in significant over-diagnosis.

It has been found that just 22 per cent of schoolchildren diagnosed in that way actually have the allergy when they are fed peanuts in a medical setting, known as an oral food challenge test.

However, although eating peanuts is a more accurate way of diagnosing the allergy, it leaves sufferers at risk of deadly anaphylactic shock.

Now, a Medical Research Council team has realised it can predict the allergy with 98 per cent accuracy simply by looking at how certain types of cells in the blood, known as mast cells, react to the presence of peanuts.

Dr Alexandra Santos, an MRC clinician scientist at King’s College London, and lead author of the study published in the Journal of Allergy and Clinical Immunolog y, said: “The new test … would reduce by two thirds the number of expensive, stressful oral food challenges conducted, as well as saving children from experiencing allergic reactions.”