Diagnostic performance and clinical utility of open oral food challenges using double-blind, placebo-controlled food...

Double-blind, placebo-controlled food challenges (DBPCFCs) are regarded as the reference standard for diagnosing IgE-mediated food allergy owing to their objectivity and ability to minimize bias. However, DBPCFCs are logistically complex, time-consuming, and not always feasible in routine clinical settings. In contrast, open oral food challenges (OFCs) are more accessible and widely used but potentially less reliable due to a lack of blinding. We evaluated the diagnostic performance of open OFCs and descriptively compared their clinical utility.

We conducted a systematic review of literature available in the Cochrane Central Register of Controlled Trials, PubMed, and Ichushi databases between January 1, 2000, and December 31, 2024, incorporating randomized controlled trials and observational studies in which both open OFCs and DBPCFCs were performed. Risk of bias (RoB) was assessed using QUADAS-2.

Eight studies were included. Using DBPCFC as the reference standard, the diagnostic performance of open OFC was as follows: sensitivity, 0.91-0.92 (n = 2); specificity, 0.83-1.00 (n = 3); positive predictive value, 0.00-0.89 (n = 6); and negative predictive value, 0.88-0.97 (n = 2). RoB was high mainly owing to the patient selection and the flow and timing domains.

Given the small number of studies examined, high RoB, and heterogeneity among studies, caution is needed in generalizing these results. Although a negative open OFC result may be reliable, the current evidence is insufficient to establish open OFCs as a complete substitute for DBPCFCs, and large-scale, standardized studies in more diverse populations are needed to clarify their diagnostic performance and clinical utility.