Total testosterone assays in women with polycystic ovary syndrome: precision and correlation with hirsutism.

Abstract

CONTEXT:

There is no standardized assay of testosterone in women. Liquid chromatography mass spectrometry (LC/MS) has been proposed as the preferable assay by an Endocrine Society Position Statement.

OBJECTIVE:

The aim was to compare assay results from a direct RIA with two LC/MS.

DESIGN AND SETTING:

We conducted a blinded laboratory study including masked duplicate samples at three laboratories--two academic (University of Virginia, RIA; and Mayo Clinic, LC/MS) and one commercial (Quest, LC/MS).

PARTICIPANTS AND INTERVENTIONS:

Baseline testosterone levels from 596 women with PCOS who participated in a large, multicenter, randomized controlled infertility trial performed at academic health centers in the United States were run by varying assays, and results were compared.

MAIN OUTCOME MEASURE:

We measured assay precision and correlation and baseline Ferriman-Gallwey hirsutism scores.

RESULTS:

Median testosterone levels were highest with RIA. The correlations between the blinded samples that were run in duplicate were comparable. The correlation coefficient (CC) between LC/MS at Quest and Mayo was 0.83 [95% confidence interval (CI), 0.80-0.85], between RIA and LC/MS at Mayo was 0.79 (95% CI, 0.76-0.82), and between RIA and LC/MS at Quest was 0.67 (95% CI, 0.63-0.72). Interassay variation was highest at the lower levels of total testosterone (≤50 ng/dl). The CC for Quest LC/MS was significantly different from those derived from the other assays. We found similar correlations between total testosterone levels and hirsutism score with the RIA (CC=0.24), LC/MS at Mayo (CC=0.15), or Quest (CC=0.17).

CONCLUSIONS:

A testosterone RIA is comparable to LC/MS assays. There is significant variability between LC/MS assays and poor precision with all assays at low testosterone levels.

• Authors: Richard S Legro, William D Schlaff, Michael P Diamond, Christos Coutifaris, Peter R Casson, Robert G Brzyski, Gregory M Christman, J C Trussell, Stephen A Krawetz, Peter J Snyder, Dana Ohl, Sandra A Carson, Michael P Steinkampf, Bruce R Carr, Peter G McGovern, Nicholas A Cataldo, Gabriella G Gosman, John E Nestler, Evan R Myers, Nanette Santoro, Esther Eisenberg, Meizhuo Zhang, Heping Zhang, Reproductive Medicine Network
• Journal: The Journal of clinical endocrinology and metabolism (J Clin Endocrinol Metab) Vol. 95 Issue 12 Pg. 5305-13 (Dec 2010) ISSN: 1945-7197 [Electronic] United States
• PMID: 20826578 (Publication Type: Journal Article, Multicenter Study, Randomized Controlled Trial, Research Support, N.I.H., Extramural)

Chemical References

• Testosterone

Topics

• Chromatography, Liquid (methods)
• Cross Reactions
• Female
• Hirsutism (blood, complications)
• Humans
• Male
• Mass Spectrometry (methods)
• Polycystic Ovary Syndrome (blood, complications)
• Radioimmunoassay
• Regression Analysis
• Sex Characteristics
• Testosterone (blood)
• United States