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How it is performed:
| • | performed using a device such as a bifurcated needle or lance to puncture skin through a glycerinated extract of food with the appropriate positive (histamine) and negative (saline-glycerine) controls |
| • | a local wheal and flare response indicates the presence of food specific IgE antibody |
| • | results are evaluated at 15 minutes and wheals of 3mm or larger are considered positive |
Relevance:
| • | most informative when test is negative because negative predictive value of the tests is very high (>95%) |
| • | stated otherwise: a negative test virtually rules out IgE mediated food allergy to the food in question |
| • | unfortunately, the positive predictive value of the test is on the order of 30% |
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