Comparison of thyroid hormones reference intervals based on thyroid antibody levels: A multicenter study.

Area of Science:

• Endocrinology
• Clinical Chemistry
• Laboratory Medicine

Background:

• Thyroid hormone reference intervals (RI) are essential for diagnosing thyroid dysfunction.
• Thyroid autoantibodies can interfere with immunoassay measurements, potentially affecting RI.

Purpose of the Study:

• To determine thyroid hormone RI stratified by thyroid antibody status.
• To evaluate the influence of different autoanalyzer kits on these RI.

Main Methods:

• Reference intervals for TSH, fT4, and fT3 were calculated using the R statistical program and RefineR algorithm.
• Data were analyzed separately for antibody-positive (Ab(+)) and antibody-negative (Ab(-)) individuals.

Main Results:

• Significant differences in RI were observed between Ab(+) and Ab(-) groups across various autoanalyzers.
• TSH RI showed notable variations, particularly with Abbott and Siemens kits, with higher ranges in Ab(+) females and significant differences in males across Roche and Beckman.
• fT4 RI also displayed differences, with Roche showing increased values in Ab(+) females and Beckman/Siemens indicating notable changes in males.

Conclusions:

• Antibody status is a significant factor influencing thyroid hormone RI.
• The study underscores the necessity for developing antibody-specific RI and improving standardization in their establishment.