ASSESSMENT OF MALE ANDROGEN STATUS: A SURVEY ON MEASUREMENT AND REPORTING OF TT, SHBG AND FT IN CLINICAL LABORATORIES ACROSS EUROPE

madman · Feb 5, 2025

ASSESSMENT OF MALE ANDROGEN STATUS: A SURVEY ON MEASUREMENT AND REPORTING OF TOTAL TESTOSTERONE, SEX HORMONE-BINDING GLOBULIN AND FREE TESTOSTERONE IN CLINICAL LABORATORIES ACROSS EUROPE

N.Narinx, J. A. Nyamaah, K. David, V. Sommers, J. Walravens, T. Fiers, B. Lapauw, B. Decallonne, F. Claessens, J. Billen,P. Vermeersch, D. Vanderschueren, L. Antonio

1Laboratory of Clinical and Experimental Endocrinology, KU Leuven, Leuven, Belgium,
2Laboratory of Molecular Endocrinology, KU Leuven, Leuven, Belgium,
3Department of Internal Medicine and Pediatrics, UZ Gent, Ghent, Belgium,
4Department of Laboratory Medicine, UZ Gent, Ghent, Belgium,
5Department of Laboratory Medicine, UZ Leuven, Leuven,Belgium

Objectives

Standardization for biochemical assessment of suspected hypogonadism is lacking, leading to methodological inconsistencies between clinical laboratories and varying reference ranges, warranting careful interpretation by clinicians This survey investigated methodological differences regarding biochemical assessment of androgens in men, focusing on total testosterone (T), sex hormone-binding globulin (SHBG) and free T, in clinical laboratories throughout Europe.

Methods

An internet-based survey was distributed from December 2022 till December 2023 by the Royal Belgian Society for Laboratory Medicine (RBSLM), the Dutch Association for Clinical Chemistry and Laboratory Medicine (NVKC), the European Academy for Andrology (EAA), the European Federation for Laboratory Medicine (EFLM), the European Society for Sexual Medicine (ESSM) and Andronet. Additionally, all Belgian clinical laboratories were directly contacted by email. Survey topics included sampling, methodology, reference ranges and reporting.

Results

A total of 124 unique records were analyzed, representing clinical laboratories from 27 different European countries. For total T, only 43.0% (52/122) recommended a sampling time, even fewer recommended sampling in a fasting state (25.4%, 31/122). Total T was quantified by enzyme-linked immunoassay (IA) (72.7%, 88/121), mass spectrometry (MS) (8.3%, 10/121), radioimmunoassay (RIA) (1.7%, 2/121), or a combination (17.3%, 21/121). Age-stratified total T reference ranges were used by most laboratories (IA: 79.0% [74/94] vs MS: 70.8% [17/24]) with IA reference ranges often supplied by the assay manufacturer (70.8%, 63/89), while MS reference ranges were often in-house developed (42.9%, 9/21). SHBG quantification was uniformly performed by IA, with age-stratified reference ranges (65.0%, 52/80), mainly provided by the assay manufacturer (83.1%, 64/78). Free T was used by 69.0% (66/95) of laboratories, either through calculation (cFT, 79.3%, 46/58) or measurement (mFT, 10.3%, 6/58) or a combination (10.3%, 6/58). cFT was predominantly calculated with the Vermeulen formula (84.2%, 48/57). mFT was assessed by direct IA/RIA (60.0%, 6/10 and 20.0%, 2/10) or MS after equilibrium dialysis or liquid-liquid extraction(20.0%, 2/10).

Conclusion

This survey highlights methodologic variability in assessing androgen status, suggesting inconsistent adherence to clinical guidelines. It emphasizes the need for harmonization, the adoption of age-specific reference ranges and, specifically for free T, standardized methods.

madman · Feb 5, 2025

Thread 'Free Testosterone - Harmonize diagnostic efforts in steroid hormonology'

Mar 17, 2023

Measurement and reporting of clinical testosterone diagnostics: a European survey (2023)

*Three fractions circulate in plasma: the unbound (free) fraction, the fraction bound to specific binding proteins, such as sex hormone-binding globulin (SHBG) and vitamin D binding protein (DBP); and the albumin-bound fraction

*The equilibrium state between these fractions is characterized not only by total hormone concentration but also by BP concentration and binding affinities for their respective metabolites1

*The use of calculators, relying on...

madman · Feb 5, 2025

Thread 'Age-stratified reference ranges for directly measured (ED LC-MS/MS) serum free testosterone in healthy men'

May 11, 2024

Just to be clear up any confusion this is Fiers camps data for mFT reference ranges not the harmonized reference range being worked on by the CDC.

*Serum samples were analyzed from healthy men participating in the SIBLOS/SIBEX and EMAS studies, both population-based cohort studies

* mFT levels were measured in 867 men using ED LC-MS/MS as previously reported (1). Subsequently, 95% reference ranges were determined using the non-parametric method

Reference: 1. Fiers T, Wu F, Moghetti P, Vanderschueren D, Lapauw B, Kaufman JM. Reassessing Free-Testosterone...

*We established mFT reference ranges for healthy men aged 18 to 69 years

We present 95% mFT age-stratified reference ranges

Age category (years)	Median mFT (ng/dl)	95% mFT reference range (ng/dl)
18-29 (n=140) 30-39 (n=252)	12.0 9.8	6.7-25.3 4.9-18.5
40-49 (n=207)	8.1	4.3.14.2
50-59 (n=146)	7.1	3.8-12.8
60-69 (n=126)	6.4	3.4-11.7
70-79 (n=125)	5.6	2.7-8.7

*The gold-standard for the determination of FT levels is considered to be directly measured free testosterone (mFT) using equilibrium dialysis followed by mass spectrometry (ED LC-MS/MS). However, no widely accepted reference ranges are available for this clinical parameter. We established mFT reference ranges for healthy men aged 18 to 69 years

*Serum samples were analyzed from healthy men participating in the SIBLOS/SIBEX and EMAS studies, both population-based cohort studies

* mFT levels were measured in 867 men using ED LC-MS/MS as previously reported (1).

Reference: 1. Fiers T, Wu F, Moghetti P, Vanderschueren D, Lapauw B, Kaufman JM. Reassessing Free-Testosterone Calculation by Liquid Chromatography–Tandem Mass Spectrometry Direct Equilibrium Dialysis. J Clin Endocrinol Metab. 2018;103(6). doi:10.1210/jc.2017-02360

Reassessing Free-Testosterone Calculation by Liquid Chromatography–Tandem Mass Spectrometry Direct Equilibrium Dialysis

Reassessment of FT in women and men with state-of-the-art methodology confirms previously established FT percentages but highlights limitations of differen

academic.oup.com

In the current study, we used a state-of-the-art direct ED method to reassess FT in sets of representative serum samples. This method takes advantage of the ability of a highly sensitive and accurate measurement of T by liquid chromatography–tandem mass spectrometry (LC-MS/MS) to reliably measure the low FT concentration directly in the dialysate after ED. This more straightforward method avoids potential sources of inaccuracy in indirect ED, such as those resulting from tracer impurities or from measures to limit their impact (e.g., sample dilution). We then used the measured FT results to re-evaluate some characteristics of two more established and a more recently proposed calculations for estimation of FT.