5α-reductase inhibitors: Evaluation of their potential confounding effect on GC-C-IRMS doping analysis

Evaluation of longitudinal 13 C IRMS data in antidoping analysis

The detection of testosterone and its precursors' abuse in Antidoping sports analysis, is based on the longitudinal evaluation of markers of the urinary endogenous steroid profile. A Bayesian statistical approach is applied, allowing the establishment of credible intervals of the selected parameters for every athlete. Samples showing values outside the acceptable boundaries are selected for additional confirmation by isotope ratio mass spectrometric (IRMS) analysis. The alterations of the IRMS values last longer than the alterations of the steroid profile. Then the application of IRMS to a larger number of samples, at a screening level, would presumably allow detection of additional positive cases. The steroid profile and IRMS data can be treated using the same Bayesian inference procedure. In non-sports population, we have demonstrated the stability of IRMS data. In this work, we studied the variability of these data in real conditions, in samples collected on athletes subjected to anti-doping analyses over the years. The data obtained confirmed previous observations and the applicability of the proposed approach. The results of cases where confounding factors of the steroid profile were reported are discussed, showing that in most of the cases no significant changes are observed over the absolute delta values. Changes in diet may significantly change the absolute delta values but not the ones relative to endogenous reference compounds. Finally, a case that could have been evaluated as normal with the current approach without a thorough review of the data, was detected as positive by the proposed approach, demonstrating the benefit of its application.

Annual banned-substance review: Analytical approaches in human sports drug testing 2020/2021

Most core areas of anti-doping research exploit and rely on analytical chemistry, applied to studies aiming at further improving the test methods' analytical sensitivity, the assays' comprehensiveness, the interpretation of metabolic profiles and patterns, but also at facilitating the differentiation of natural/endogenous substances from structurally identical but synthetically derived compounds and comprehending the athlete's exposome. Further, a continuously growing number of advantages of complementary matrices such as dried blood spots have been identified and transferred from research to sports drug testing routine applications, with an overall gain of valuable additions to the anti-doping field. In this edition of the annual banned-substance review, literature on recent developments in anti-doping published between October 2020 and September 2021 is summarized and discussed, particularly focusing on human doping controls and potential applications of new testing strategies to substances and methods of doping specified in the World Anti-Doping Agency's 2021 Prohibited List.