Predicting Baked Milk and Baked Egg Challenge Outcomes with Serum Specific IgE Levels
Monday, March 5, 2018
South Hall A2 (Convention Center)
Samantha M Knox, MD, Alton Lee Melton, MD
RATIONALE: Serum specific IgE levels can be used to predict the likelihood of reacting on food challenge. Specific IgE parameters for predicting a positive challenge to baked egg and baked milk have not yet been established. We aimed to identify these sIgE parameters.

METHODS: We retrospectively reviewed 857 charts of pediatric patients who underwent food challenges at a tertiary care center from January 2013 to May 2017. Demographics and clinical information including age, foods challenged, egg white and cow's milk sIgE levels, and challenge outcomes were collected and evaluated using ROC analysis.

RESULTS: There were 158 baked challenges: 109 baked egg and 49 baked milk in patients aged 11 months to 15 years old. Of the 109 baked egg challenges, 32% failed (35/109), where sIgE ranged from 0.53 to >100 kU/L (median 6.31 kU/L). For baked egg, sIgE of 4.46 kU/L demonstrated a 50% PPV for failed challenge (AUC 0.65, sensitivity 57%, specificity 73%). Of the 49 baked milk challenges, 20% failed (10/49), where sIgE ranged from 2.16 to 39 kU/L (median 18.2 kU/L). For baked milk, sIgE of 15.60 kU/L demonstrated a 43% PPV for failed challenge (AUC 0.71, sensitivity 60%, specificity 80%).

CONCLUSIONS: In our study, baked egg and baked milk challenges had higher rates of failure. We identified egg sIgE level of 4.46 kU/L and milk sIgE level of 15.6 kU/L with positive predictive values of 50% and 43%, respectively, for failed baked challenge. This information may aid clinicians in counseling parents regarding appropriate timing of baked challenges.