Abstract

The accurate quantification of the six endogenous anabolic steroids androsterone (A), etiocholanolone (Etio), testosterone (T), epitestosterone (E), 5α-androstane-3α,17β-diol (Adiol) and 5β-androstane-3α,17β-diol (Bdiol) for the purpose of the steroid profile model of the Athlete Biological Passport is of utmost importance. Since urinary certified reference material for the six mentioned target analytes is limited, the evaluation of steroid profile results reported by the laboratories in External Quality Assessment Scheme (EQAS) tests is assessed using z-scores. Currently the community of doping control laboratories utilizes GC quadrupole MS instruments to determine steroid profile values. Steroid profile results of 18 urine samples, distributed for interlaboratory testing (WADA EQAS exercise), obtained from GC-MS and GC-MS/MS were evaluated based on z-scoring in order to check the GC-MS/MS results for feasibility. Minor differences in concentrations for the six target steroids were detected. An extended variation for T/E is shown between the different technologies, mainly caused by the high specificity of GC-MS/MS. Most important is the examination of the target relative standard deviation (TSD) for T/E, which is currently fixed at 10%. An extention up to 20% (which is in line with most of the endogenous steroids) would lead to an elimination of questionable/unsatisfactory results of the presented data set. Verf.-Referat