Detection of Testosterone Micro-dosing in Healthy Females.

The ready detectability of synthetic androgens by mass spectrometry (MS)-based antidoping tests has reoriented androgen doping to using testosterone (T) which must be distinguished from its endogenous counterpart making detection of exogenous T harder. We investigated urine and serum steroid and hematological profiling individually and combined to determine the optimal detection model for T administration in women. Twelve healthy females provided six paired blood and urine samples over two weeks prior to treatment consisting of 12.5 mg T in a topical transdermal gel applied daily for seven days. Paired blood and urine samples were then obtained at the end of treatment and days 1, 2, 4, 7 and 14 days later. Compliance with treatment and sampling was high and no adverse effects were reported. T treatment significantly increased serum and urine T, serum DHT, urine 5α androstane-3α,17β-diol (5α diol) epitestosterone (E) and urine T/E ratio with a brief window of detection (2-4 days) as well as total and immature (medium and high fluorescence) reticulocytes which remained elevated over the full 14 post-treatment days. Carbon isotope ratio MS as well as the OFF and ABPS scores were not discriminatory. The optimal multivariate model to identify T exposure combined serum T, urine T/E ratio with three hematological variables (% high fluorescence reticulocytes, mean corpuscular hemoglobin and volume) with the five variables providing 93% correct classification (4% false positive, 10% false negatives). Hence combining select serum and urine steroid MS variables with reticulocyte measures can achieve a high but imperfect detection of T administration to healthy females.