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 Kairistoʹs 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.