The reliability and validity of provocative food testing: a critical review

Clinical reports have advocated intradermal and sublingual provocative food testing as effective methods of identifying food sensitivities. However, studies assessing their reliability and/or validity have generally reached negative conclusions. These studies commonly have serious flaws in design and analysis. These include: (1) the administration of food antigens to subjects without verifying sensitivity to them, and then comparing responses to antigens and placebos, (2) the failure to implement double-blind procedures with placebo controls, (3) the failure to analyse results statistically, and (4) improper statistical analysis. In some cases, re-analysis of the data provided seriously affects the conclusions of the study. Overall, the evidence suggests that both intradermal and sublingual provocative food tests are capable of provoking reactions above placebo levels, but whether they are sufficiently reliable and valid to be clinically useful is questionable.