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


METHODS
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).


METHODS
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.


METHODS
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.
Legro
Richard S
RS
Department of Obstetrics and Gynecology, Pennsylvania State University, College of Medicine, M. S. Hershey Medical Center, 500 University Drive, H103, Hershey, Pennsylvania 17033, USA. RSL1@psu.edu
Schlaff
William D
WD
Diamond
Michael P
MP
Coutifaris
Christos
C
Casson
Peter R
PR
Brzyski
Robert G
RG
Christman
Gregory M
GM
Trussell
J C
JC
Krawetz
Stephen A
SA
Snyder
Peter J
PJ
Ohl
Dana
D
Carson
Sandra A
SA
Steinkampf
Michael P
MP
Carr
Bruce R
BR
McGovern
Peter G
PG
Cataldo
Nicholas A
NA
Gosman
Gabriella G
GG
Nestler
John E
JE
Myers
Evan R
ER
Santoro
Nanette
N
Eisenberg
Esther
E
Zhang
Meizhuo
M
Zhang
Heping
H
D002853:Chromatography, Liquid / Q000379:methods; D003429:Cross Reactions; D005260:Female; D006628:Hirsutism / Q000097:blood* / Q000150:complications; D006801:Humans; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D011085:Polycystic Ovary Syndrome / Q000097:blood* / Q000150:complications; D011863:Radioimmunoassay; D012044:Regression Analysis; D012727:Sex Characteristics; D013739:Testosterone / Q000097:blood*; D014481:United States
D013739:Testosterone
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