Improved method of detection of testosterone abuse by gas chromatography/combustion/isotope ratio mass spectrometry analysis of urinary steroids.
The current approach to detection of doping with testosterone is based on measuring the testosterone to epitestosterone ratio (T/E) in urine by gas chromatography/mass spectrometry. The median T/E for healthy males who have not used T is about 1.0. In a single urine, a T/E lower than six leads to a negative report even though it does not exclude T administration. A value greater than six indicates possible T administration or a naturally elevated ratio. It has been shown previously that the carbon isotope ratio of urinary T changes after T administration. In this study a potential confirmation method for T abuse was optimized. Gas chromatography/combustion/carbon isotope ratio mass spectrometry (GC/C/IRMS) was used to analyze two T precursors (cholesterol and 5-androsten-3 beta, 17 beta-diol) and two T metabolites (5 alpha- and 5 beta-androstane-3 alpha, 17 beta-diol) in addition to T itself in each of 25 blind urines collected from eight healthy men before, during or after T administration. The carbon isotope ratios of T and the metabolites were lower after T administration. The relationships among the variables were studied using multivariate analysis and beginning with principal components analysis; cluster analysis revealed that the data are composed of two clusters, and classified the samples obtained after T administration in one cluster and the remainder in the other; discriminant analysis correctly identified T users. The measurement of carbon isotope ratios of urinary androgens is comparable to the T/E > 6 test and continues to show promise for resolving cases where doping with T is suspected.
Aguilera
R
R
Service Central d'Analyse, CNRS, Vernaison, France.
Becchi
M
M
Casabianca
H
H
Hatton
C K
CK
Catlin
D H
DH
Starcevic
B
B
Pope
H G
HG
D000328:Adult; D002247:Carbon Isotopes; D018592:Cross-Over Studies; D004300:Doping in Sports; D004311:Double-Blind Method; D004845:Epitestosterone / Q000652:urine; D008401:Gas Chromatography-Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D015813:Substance Abuse Detection / Q000379:methods*; D013739:Testosterone / Q000652:urine*
D002247:Carbon Isotopes; D013739:Testosterone; D004845:Epitestosterone