SUN-390 Optimal Screenig Capillary TSH Cut Off for Congenital Hypothyroidism: Results from a Pilot New Born Screening Study

Abstract Disclosure: M. Darshan: None. Prashant Verma, Mukesh Darshan,Seema KapoorObjective: To determine an appropriate cut-off of capillary Thyroid stimulating hormone (TSH) for congenital hypothyroidism. Study design: Cross-sectional. Participants: 174,000 neonates born in different hospitals of Delhi, India, from November 2014 to October 2016. Main outcome measures: Correlation between initial and repeat capillary TSH level and subsequent venous free thyroxine (fT4) level Results: 102 newborns with initial/ repeat capillary TSH level of ≥20 mIU/L (n=174) were confirmed to have congenital hypothyroidism at mean (SD) age of 5 (4) days. A good correlation between capillary TSH level and confirmatory venous fT4 level and postnatal age of sampling was obtained (r -0.6,-0.4). The area under the ROC curve (AUC) was 0.81 (95%CI 0.75 to 0.88), indicating referral capillary TSH level of 20 mIU/L to be a good predictor of subsequent high venous TSH level. Conclusion: A cut off of ≥20 mIU/L for capillary TSH screening beyond 24 hours of life is optimal in the Indian setting for deciding further recall and workup, keeping a balance between sensitivity and recall rate. Presentation: Sunday, July 13, 2025