Diagnostic Decision Points of Specific Immunoglobulin E Concentrations for Seafood Allergies in Korean Children: A Nationwide Multicenter Study

Shellfish and fish are common causes of food allergy (FA) in Asia, with significant prevalence rates reported across various countries. This study aimed to identify the diagnostic decision points (DDPs) for shrimp, crab, and cod allergies in Korean children. We enrolled participants aged 18 years or younger with suspected shrimp, crab, or cod allergies through a retrospective review of medical records from a nationwide 14-center study between January 2018 and March 2022. FA was diagnosed using an open oral food challenge or a reproducible and convincing history with positive serum specific immunoglobulin E (sIgE) levels. The sIgE cut-off values for shrimp, crab, and cod were determined by analyzing receiver operating characteristic curves. Out of 266 children, 90 (33.8%) were confirmed to have a shrimp allergy. Crab allergies were found in 37 (39.8%) of 93 children. Of 66 children, 15 (22.7%) were found to be allergic to cod. The optimal sIgE cut-off values based on the largest area under the curve were 1.43, 3.25, and 2.05 kU/L for shrimp, crab, and cod, respectively. Levels of sIgE with more than 90% positive predictive value (PPV) were 33.8, 47.5, and 29.9 kU/L for shrimp, crab, and cod, respectively. Levels of sIgE with greater than 90% negative predictive value (NPV) were 0.36, 0.04, and 3.93 kU/L for shrimp, crab, and cod, respectively. Our results suggest that DDPs of sIgE levels with high PPV and NPV can be used to diagnose shrimp, crab, and cod allergies in Korean children.