Biomarkers of testosterone doping: GC-C-IRMS confirmations at scale

Code: 241A06JFN

Testosterone (T) abuse is still relatively popular among athletes despite our ability to unambiguously differentiate between T originating from an individual’s body and synthetic T using carbon stable isotope analysis. The cost prohibitive nature of this analysis makes it so that not all urine samples which are collected can be analyzed using this procedure. As such, several steps have been taken by WADA to target samples for this analysis based on several markers of T abuse which have been shown as likely to be influenced by T doping. Currently, these primary markers of T abuse are checked using athlete biological passports and flagged for T confirmation when a suspicious steroid profile is seen. This approach has been relatively successful, as stable isotope confirmation tends to have one of the highest positivity rates per sample analyzed across WADA globally. A blind spot exists due to our ability to confirm T abuse using stable isotope analysis is greater than our ability to decide which samples are to be subjected to this type of analysis, with the makers used to flag samples returning to baseline levels before the stable isotope signature returns to base levels. The extent at which T abuse is possibly under reported must be verified through the confirmation of a significant number of real athlete samples and ideally, new biomarkers of T abuse need to be discovered. We propose to analyse a series of athlete urine samples by 4 complementary analysis procedures targeting a variety of both phase 1 and phase 2 metabolites with all samples being confirmed using stable isotope analysis, allowing us to verify the frequency of T abuse being under reported while also allowing us to better target future samples for T confirmation.