Variability of the urinary and blood steroid profiles in healthy women
The steroidal module of the Athlete Biological Passport (ABP) targets the use of exogenous androgenous anabolic steroids (EAAS) in elite sport by monitoring urinary steroid profiles. Urine and blood samples were collected weekly during two consecutive OCP cycles (8 weeks) in 15 physically active women to investigate the low urinary steroid concentrations and putative confounding effect of OCP. In urine, testosterone (T) and/or epitestosterone (E) were below the limit of quantification of 1 ng/mL in 62% of the samples. Biomarkers variability ranged between 31% and 41%, with a significantly lesser variability for ratios (with the exception of T/E (41%)): 20% for androsterone/etiocholanolone (p < 0.001) and 25% for 5-androstane-3,17{beta}-diol/5{beta}-androstane-3,17{beta}-diol (p < 0.001). In serum, variability for testosterone (T; 24%), androstenedione (A4; 23%), dihydrotestosterone (DHT; 19%) and T/A4 (16%) was significantly lower than urinary biomarkers (p < 0.001). Urinary A/Etio increased by > 18% after the first two weeks (p < 0.05) following blood loss. In contrast, T (0.98 nmol/L during the first week), and T/A4 (0.34 the first week) decreased significantly by more than 25% and 17% (p<0.05), respectively in the following weeks. Our results outline steroidal variations during the OCP cycle highlighting exogenous hormonal preparations as confounder for steroid concentrations in blood. Low steroid levels in urine samples have a clear detrimental impact on the subsequent interpretation of steroidal variations for the ABP. With a greater analytical sensitivity and lesser variability for steroids in serum vs. urine in healthy active women, serum represents a complementary matrix to urine in the ABP steroidal module.