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

TL;DR

This study shows that thyroid hormone reference intervals differ based on thyroid antibody levels, suggesting the need for antibody-specific standards.

Contribution

The study introduces antibody-specific reference intervals for thyroid hormones, revealing significant differences based on antibody status.

Findings

Thyroid-stimulating hormone (TSH) reference intervals varied significantly between antibody-positive and antibody-negative individuals across different analyzers.

Reference intervals for free thyroxine (fT4) were notably affected by antibody status in females using Roche analyzers.

The study emphasizes the importance of adjusting reference intervals according to thyroid antibody status for more accurate thyroid assessments.

Abstract

This study aimed to determine reference intervals (RI) for thyroid hormones based on thyroid antibody levels using different autoanalyzer kits.

RI for Thyroid-stimulating hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3) were determined according to thyroid antibody levels and independently of thyroid antibody levels using the R statistical program and RefineR algorithm.

Significant differences in RIs were found between antibody-positive (Ab(+)) and antibody-negative (Ab(–)) individuals. TSH RI varied most notably in Abbott and Siemens analyzers. In females, Abbott showed higher TSH RIs in the Ab(+) group (0.41–7.44 mU/L) than in Ab(–) (0.24–3.50 mU/L). In males, Roche and Beckman exhibited the greatest differences (Roche Ab(+): 0.19–5.77; Ab(–): 0.44–3.63; Beckman Ab(+): 0.12–5.23; Ab(–): 0.39–3.96 mU/L). For fT4, Roche showed increased RIs in females with Ab(+) status (11.42–20.42 vs. 10.34–19.35 pmol/L). In males, Beckman and Siemens autoanalyzers also indicated notable differences.

Antibody status significantly affects thyroid hormone RI, particularly for TSH. These findings highlight the need for antibody-specific RI and further standardization in establishing reference intervals.

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