Introduction: Buckwheat (BW) is considered to be one of the most important food allergens, and positive skin tests are found in about 5% of Koreans. We investigated the positive and negative predictive values of BW-specific IgE in subjects with a BW allergy in order to reduce the need for buckwheat challenge, which can be more riskier than other causes of food allergies.
Methods: Twenty-eight BW allergic subjects with symptoms after BW Open food challenge and 16 asymptomatic control subjects with positive skin test to BW were recruited. Serum samples from all patients were analyzed for BW-specific IgE antibodies using the Pharmacia CAP System.
Results: According to the receiver operator characteristic (ROC) analysis, the optimal cutoff level of BW-specific IgE, as the definitions of serum BW-specific IgE positive, was 1.26 kUA/l. With this selected cutoff level, the sensitivity, specificity, positive and negative predictive values were 93.10, 93.33, 79.75 and 97.96%, respectively.
Conclusion: The use of the optimal cutoff level, 1.26 kUA/l, that simultaneously maximizes sensitivity and specificity, would be helpful for avoiding unnecessary risky challenge in children with a strong clinical history and skin test responses.