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

Steroids. 2009 Mar;74(3):365-8. doi: 10.1016/j.steroids.2008.11.003. Epub 2008 Nov 13.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Bayes Theorem*
  • Doping in Sports*
  • Epitestosterone / urine
  • Genotype*
  • Glucuronosyltransferase / genetics
  • Humans
  • Male
  • Middle Aged
  • Minor Histocompatibility Antigens
  • Polymorphism, Genetic / genetics*
  • Substance Abuse Detection / methods*
  • Testosterone / urine*
  • Young Adult


  • Minor Histocompatibility Antigens
  • Testosterone
  • Epitestosterone
  • Glucuronosyltransferase
  • UGT2B17 protein, human