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Cited by 172Hormonal and reproductive studiesClinical Laboratory Practices and Quality ControlAdrenal Hormones and Disorders

ORIGINAL ARTICLE: Accuracy of calculated free testosterone formulae in men

Ly, Lam P., Sartorius, Gideon, Hull, Laura, Leung, Andrew, Swerdloff, Ronald S., Wang, Christina, Handelsman, David J.·2010·Clinical Endocrinology
DOI 10.1111/j.1365-2265.2010.03804.x
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Abstract

Summary: Background As reference laboratory methods for measuring free testosterone (FT) by equilibrium dialysis (ED) are laborious, costly and nonautomatable, FT levels are often calculated (cFT) rather than measured. However, the predictive accuracy of such estimates in routine use relative to laboratory measurements is not well defined. We provide a large‐scale evaluation of the predictive accuracy for different FT formulae compared with laboratory ED measurement and an analysis of clinical factors that may influence accuracy. Methods The accuracy of five different cFT formulae (two equilibrium binding, three empirical) based on immunoassays of total testosterone (TT) and SHBG was evaluated by comparing those estimates with FT measurement by ED in 2159 serum samples from men at a single research laboratory over several years. Results cFT formulae show systematic discrepancies from the two equilibrium‐binding formulae. One empirical formula overestimated FT relative to ED measurements, whereas two newer empirical cFT formulae were more concordant. These discrepancies persisted after correction for serum albumin and were not influenced by obesity, ethnicity or gonadal status. Conclusions Commonly used cFT formulae significantly overestimate FT relative to laboratory measurement by ED in male serum samples. The accuracy of the formulae is not influenced by correction for serum albumin, obesity, ethnicity or gonadal status. Such inaccuracy relative to the reference method renders some cFT estimates unreliable for evaluating androgen deficiency as recommended by clinical best practice guidelines.

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Authors
Ly, L. P., Sartorius, G., Hull, L., Leung, A., Swerdloff, R. S., Wang, C., & Handelsman, D. J.
Affiliations
  • The University of Sydney (AU)
  • The Lundquist Institute (US)
Corresponding author
Handelsman, David J.
ORCID
Venue
Clinical Endocrinology
Publisher
Wiley
Published
2010-08-17
Volume
73
Issue
3
Pages
382-388
ISSN
  • 0300-0664 (ISSN-L)
  • 1365-2265
DOI
10.1111/j.1365-2265.2010.03804.x
OpenAlex
W1596025924
Cited by
172
References
5
Citations by year
2026: 2 · 2025: 6 · 2024: 5 · 2023: 6 · 2022: 8 · 2021: 7 · 2020: 11 · 2019: 3 · 2018: 11 · 2017: 18 · 2016: 12 · 2015: 17 · 2014: 20 · 2013: 17 · 2012: 15
FWCI
11.13
Type
journal article
Language
en
Open access
closed
Licence
onlinelibrary.wiley.com/termsAndConditions#vor (vor)
Locations
  • Clinical Endocrinology (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • National Research Foundation
  • National Center for Research Resources (MO1-RR00425, M01RR000425)
  • NIH Clinical Center
Topics
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Hormonal and reproductive studies
  • Health Sciences › Medicine › Physiology › Clinical Laboratory Practices and Quality Control
  • Health Sciences › Medicine › Endocrinology, Diabetes and Metabolism › Adrenal Hormones and Disorders
Keywords
free testosterone, equilibrium dialysis, binding equilibrium, empirical formula, total testosterone, sex hormone-binding globulin, androgen deficiency, men, prediction accuracy, obesity, ethnicity, gonadal status
MeSH terms
Adolescent, Adult, Aged, Aged, 80 and over, Algorithms, Asian, Black or African American, Gonads, Hispanic or Latino, Humans, Immunoassay, Male, Middle Aged, Serum Albumin, Sex Hormone-Binding Globulin, Testosterone, Reproducibility of Results, Body Mass Index, Logistic Models, White People, Young Adult

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