Reference Intervals for Serum Thyroid-Stimulating Hormone Based on a Recent Nationwide Cross-Sectional Study and...

Area of Science:

• Endocrinology
• Clinical Chemistry
• Population Health

Background:

• Thyroid-stimulating hormone (TSH) reference intervals (RIs) are crucial for diagnosing thyroid dysfunction.
• Existing TSH RIs may not accurately reflect diverse global populations due to variations in ethnicity and iodine status.

Purpose of the Study:

• To compare TSH reference intervals across different ethnicities and iodine statuses globally.
• To establish more accurate, population-specific TSH RIs.

Main Methods:

• Utilized primary data from a cross-sectional study in China and secondary data from online databases.
• Calculated TSH RIs using National Academy of Clinical Biochemistry standards in both reference and disease-free populations.
• Performed a meta-analysis of ethnicity- and iodine status-specific TSH RIs.

Main Results:

• The TSH RI in the disease-free population (2.33 mU/L [0.67, 7.87]) was wider than in the reference population (2.28 mU/L [0.74, 7.04]).
• Ethnic groups categorized as 'Yellows' exhibited higher TSH RIs compared to Caucasians in both reference and disease-free populations.
• Iodine sufficiency influenced TSH RIs, with varying effects on median, 2.5th, and 97.5th percentiles depending on the population group.

Conclusions:

• Ethnic background significantly impacts TSH reference intervals, with 'Yellows' showing higher RIs than Caucasians.
• Iodine status plays a role in TSH RIs, affecting different percentiles uniquely in reference versus disease-free populations.
• The study underscores the importance of considering ethnicity and iodine status for accurate TSH RI interpretation.