Diagnostic Value of Testosterone, Free Testosterone, and Free Androgen Index in Polycystic Ovary Syndrome

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 532-553-Hyperandrogenic Disorders
Basic/Clinical
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-532
Hong N Bui*1, Patrick M Sluss2, Stuart Blincko3, Dirk L Knol1, Marinus A Blankenstein4 and Annemieke C Heijboer4
1VU University Medical Center, 2Massachusetts General Hospital, Boston, MA, 3Abbott Diagnostics, Wisbaden, Germany, 4VU University Medical Center, Amsterdam, Netherlands
The introduction of more accurate methods for testosterone (T) analysis, such as liquid chromatography-tandem mass spectrometry (LC-MS/MS) or next-generation immunoassays, may assist in reaching a consensus on the definition of hyperandrogenism, one of the diagnostic criteria of polycystic ovary syndrome (PCOS). The objective of the study was to determine reliable reference intervals for T, free testosterone (fT), and free androgen index (FAI) and to test the discriminative value of these parameters in a PCOS-population using accurate methods.

Serum was obtained daily during a normal menstrual cycle from 25 healthy women who were characterized by physical and biochemical examination (743 data-points). A single serum was obtained from 43 PCOS-patients. T was measured by LC-MS/MS and by Architect® 2ndGeneration Testosterone Immunoassay (1). Sex hormone-binding globulin was measured to calculate fT (2: Vermeulen) and FAI (100*[T]/[SHBG]).

The reference intervals (central 95%) were calculated taking the underlying data structure into account, T=0.3–1.6nmol/L and 0.5–2.0nmol/L, fT=5.2–26pmol/L and 7.2–33pmol/L, and FAI=0.4–2.9 and 0.6–4.4, by LC-MS/MS and immunoassay, respectively. In healthy subjects, T, fT, and FAI levels were significantly higher mid-cycle, although a peak was not discernable in all individuals. This indicates that application of the reference ranges is valid for all phases of the menstrual cycle. The values found in PCOS-patients were 1.5nmol/L (0.6–3.2), 31pmol/L (9–60), and 3.8 (0.8–15) (median (range)) for T, fT, and FAI, respectively, by LC-MS/MS. By immunoassay, this was 1.6nmol/L (0.7–2.9), 32pmol/L (12–62), and 4.3 (1.1–16), respectively. The area under the curve of receiver operator characteristic plots were 0.84, 0.91, and 0.91 for T, fT, and FAI, respectively, by LC-MS/MS and 0.83, 0.90, and 0.89, respectively, by immunoassay.

Apart from providing reliable reference ranges, our data confirm the importance of taking SHBG into account when assessing androgen status in patients evaluated for PCOS.

(1) Bui et al, Steroids 2013;78:96-101 (2) Vermeulen et al, J Clin Endocrinol Metab 1999;84:3666-72

Disclosure: SB: Employee, Abbott Laboratories. Nothing to Disclose: HNB, PMS, DLK, MAB, ACH

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

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