Detection of erythropoietin misuse by the Athlete Biological Passport combined with reticulocyte percentage

The sensitivity of the adaptive model of the Athlete Biological Passport (ABP) and reticulocyte percentage (ret%) in detection of recombinant human erythropoietin (rHuEPO) misuse was evaluated using both a long‐term normal dose and a brief high dose treatment regime. Sixteen subjects received either 65 IU rHuEPO × kg ‐1 every second day for two weeks (normal‐dose), 390 IU rHuEPO × kg ‐1 on three consecutive days (high‐dose), or frequent placebo treatment for 13 days in a randomized, placebo‐controlled, double‐blind crossover design. Blood variables were measured 4, 11, and 25 days following treatment initiation. The ABP based on haemoglobin concentration ([Hb]) and OFF‐hr score ([Hb] – 60 × √ret%) yielded atypical profiles following both normal‐dose and high‐dose treatment (0 %, 31 %, 13 % vs. 21 %, 33 %, 20 % at days 4, 11, and 25 after normal and high dose, respectively). Including ret% as a stand‐alone marker for atypical blood profiles increased (P < 0.05) the sensitivity of the adaptive model at day 11 to 63 % and 67 % for normal‐dose and high‐dose rHuEPO administration, respectively. In conclusion, ~30 % of subjects injecting a normal‐dose rHuEPO for two weeks or a high‐dose rHuEPO for three days will present an atypical ABP profile. Including ret% as a stand‐alone parameter improves the sensitivity two‐fold.