Total Testosterone Assays in Women with Polycystic Ovary Syndrome: Precision and Correlation with Hirsutism.

Author(s): Legro RS, Schlaff WD, Diamond MP, Coutifaris C, Casson PR, Brzyski RG, Christman GM, Trussell JC, Krawetz SA, Snyder PJ, Ohl D, Carson SA, Steinkampf MP, Carr BR, McGovern PG, Cataldo NA, Gosman GG, Nestler JE, Myers ER, Santoro N, Eisenberg E, Zhang M, Zhang H, for the Reproductive Medicine Network

Affiliation(s): Department of Obstetrics and Gynecology (R.S.L., J.C.T.), Pennsylvania State University, Hershey, Pennsylvania 17033; Department of Obstetrics and Gynecology (W.D.S., N.S.), University of Colorado, Denver, Colorado 80217; Collaborative Center for Statistics in Science (M.Z., H.Z.), Yale School of Public Health, New Haven, Connecticut 06510; University of Texas Southwestern Medical Center (B.R.C.), Dallas, Texas 75390; Departments of Obstetrics and Gynecology (M.P.D., S.A.K.), Wayne State University, Detroit, Michigan 48202; Baylor College of Medicine (S.A.C.), Houston, Texas 77030; University of Alabama (M.P.S.), Birmingham, Alabama 35294; University of Pennsylvania (C.C., P.J.S.), Philadelphia, Pennsylvania 19104; University of Medicine and Dentistry of New Jersey (P.G.M.), Newark, New Jersey 07103; Stanford University (N.A.C.), Stanford, California 94305; University of Pittsburgh (G.G.G.), Pittsburgh, Pennsylvania 15208; Department of Medicine (J.E.N.), Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298; Department of Obstetrics and Gynecology and Duke Clinical Research Institute (E.R.M.), Duke University Medical Center, Durham, North Carolina 27705; Department of Medicine and Obstetrics and Gynecology (P.R.C.), University of Vermont, Burlington, Vermont 05405; Department of Obstetrics and Gynecology (R.G.B.), The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229; Department of Obstetrics and Gynecology (G.M.C., D.O.), Reproductive Sciences Program, University of Michigan, Ann Arbor, Michigan 48109; and Reproductive Sciences Branch (E.E.), Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, Maryland 20814.

Publication date & source: 2010-09-08, J Clin Endocrinol Metab., [Epub ahead of print]

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.