Substantial advantage of a combined Bayesian and genotyping approach in testosterone doping tests.


Autoria(s): Schulze J.J.; Lundmark J.; Garle M.; Ekström L.; Sottas P.E.; Rane A.
Data(s)

2009

Resumo

Testosterone abuse is conventionally assessed by the urinary testosterone/epitestosterone (T/E) ratio, levels above 4.0 being considered suspicious. A deletion polymorphism in the gene coding for UGT2B17 is strongly associated with reduced testosterone glucuronide (TG) levels in urine. Many of the individuals devoid of the gene would not reach a T/E ratio of 4.0 after testosterone intake. Future test programs will most likely shift from population based- to individual-based T/E cut-off ratios using Bayesian inference. A longitudinal analysis is dependent on an individual's true negative baseline T/E ratio. The aim was to investigate whether it is possible to increase the sensitivity and specificity of the T/E test by addition of UGT2B17 genotype information in a Bayesian framework. A single intramuscular dose of 500mg testosterone enanthate was given to 55 healthy male volunteers with either two, one or no allele (ins/ins, ins/del or del/del) of the UGT2B17 gene. Urinary excretion of TG and the T/E ratio was measured during 15 days. The Bayesian analysis was conducted to calculate the individual T/E cut-off ratio. When adding the genotype information, the program returned lower individual cut-off ratios in all del/del subjects increasing the sensitivity of the test considerably. It will be difficult, if not impossible, to discriminate between a true negative baseline T/E value and a false negative one without knowledge of the UGT2B17 genotype. UGT2B17 genotype information is crucial, both to decide which initial cut-off ratio to use for an individual, and for increasing the sensitivity of the Bayesian analysis.

Identificador

http://serval.unil.ch/?id=serval:BIB_656F0D322913

isbn:0039-128X

pmid:19056415

doi:10.1016/j.steroids.2008.11.003

isiid:000264941000012

Idioma(s)

en

Fonte

Steroids, vol. 74, no. 3, pp. 365-368

Palavras-Chave #Adolescent; Adult; Bayes Theorem; Doping in Sports; Epitestosterone/urine; Genotype; Glucuronosyltransferase/genetics; Humans; Male; Middle Aged; Polymorphism, Genetic/genetics; Substance Abuse Detection/methods; Testosterone/urine; Young Adult
Tipo

info:eu-repo/semantics/article

article