First Estimation of Reference Intervals for Thyroid-Stimulating Hormone and Thyroid Hormones in Slovenian Population

Abstract

For thyroid function estimation and clinical decision making, use of appropriate reference intervals for thyroid-stimulating hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3) is crucial. For each laboratory, establishment of own reference intervals is advised. For the first Slovenian estimation of reference intervals for thyroid hormones a large group of 1722 healthy individuals without thyroid disease was established retrospectively. Hormone analyses were performed on automated analyser Advia Centaur XP Immunoassay System (Siemens Healthineers), which reference intervals for TSH, fT4 and fT3 were 0.55–4.78 mIU/L, 11.5–22.7 pmol/L, and 3.5–6.5 pmol/L, respectively. Statistical analysis followed non-parametric percentile method. Our laboratory reference intervals for TSH, fT4 and fT3 are mostly narrower than intervals given by manufacturer. Median value, lower and upper limit for TSH, fT4 and fT3 were 1.98 (0.59–4.23) mIU/L, 14.5 (11.3–18.8) pmol/L and 4.82 (3.79–6.05) pmol/L, respectively. Most likely, an inclusion of a high number of healthy individuals without thyroid disease was a reason for such results.

Thyroid Dysfunction and Kidney Dysfunction

“…Since the determinants of age, gender, weight, genetic background, and ethnicity control THND, 2 certain populations-specific THND have been built. 3 - 5 The normal range for thyroid-stimulating hormone of 0.2–4.5 mIU/L and 8–24 pmol/L for free thyroxin were considered in assessing thyroid health status in the studied CKD cohort. However, the reference of the employed THND was not addressed.…”