Interpretation of Subjective Symptoms in Double-blind Placebo-controlled Food Challenges - Interobserver Reliability

Background: Subjective symptoms after food challenges are difficult to interpret and no standard is available. We discuss a strategy for how to interpret a diary. Furthermore, the interobserver reliability is evaluated.

Methods: Diaries for 32 patients with subjective symptoms were used. The diaries were re-evaluated with a predefined strategy by three independent observers.

Results: The proportion of positives was 21.9% among the old diagnoses, according to the new approach 34.4% (observers I and II) and 37.5% (observer III) were positive. The new approach had high interobserver reliability (97 and 100%).

Conclusions: The proportion of positives depends on how subjective symptoms are interpreted. Interpretations of subjective symptoms in diaries could be made with high interobserver reliability.