Indirect estimation of pediatric Health Related Limits for serum thyrotropin using the ADVIA Centaur analyzer

OBJECTIVES: To determine pediatric reference values for thyrotropin using Advia Centaur analyzer. DESIGN AND METHODS: The study was conducted in a large regional hospital on TSH results obtained from 5741 females and 4332 males aged 0-17 years. After the exclusion of the results outside 4 standard deviations, we calculated the Health Related Limits (HRLs) following the indirect Kairisto's procedure and using the software GraphROC. RESULTS: The lower HRL of TSH concentration was 0.70 mU/L in the years 0-11 and 0.50 mU/L in the following years. The upper TSH HRL was 6.9 mU/L in males vs. 5.7 mU/L in females in the first year and 6.7 mU/L vs. 5.3 in the period 1-2 years. The upper HRLs in females and males were similar in the following years and the upper HRL in the 13-17 years class was 3.8 mU/L. CONCLUSIONS: The indirect methods appear reliable for calculating the pediatric HRLs for TSH.