Screening for recombinant human erythropoietin using [Hb], reticulocytes, the OFF_{hr score}, OFF_{z score} and Hb_{z score}: status of the Blood Passport

摘要

Haemoglobin concentration ([Hb]), reticulocyte percentage (retic%) and OFF_{hr score} are well-implemented screening tools to determine potential recombinant human erythropoietin (rHuEpo) abuse in athletes. Recently, the International Cycling Union implemented the OFF _{z score} and the Hb _{z score} in their anti-doping testing programme. The aim of this study is to evaluate the sensitivity of these indirect screening methods. Twenty-four human subjects divided into three groups with eight subjects each (G1; G2 and G3) were injected with rHuEpo. G1 and G2 received rHuEpo for a 4-week period with 2 weeks of “boosting” followed by 2 weeks of “maintenance” and a wash-out period of 3 weeks. G3 received rHuEpo for a 10-week period (boost = 3 weeks; maintenance = 7 weeks; wash out = 1 week). Three, seven and eight of the 24 volunteers exceeded the cut-off limits for OFF_{hr score}, [Hb] and retic%, respectively. One subject from G1, nobody from G2, and seven subjects from G3 exceeded the cut-off limit for Hb _{z score.} In total, ten subjects exceeded the cut-off limit for the OFF _{z score}; two subjects from G1, two subjects from G2 and six subjects from G3. In total, indirect screening methods were able to indicate rHuEpo injections in 58% of subjects. However, 42% of our rHuEpo-injected subjects were not detected. It should be emphasised that the test frequency in real world anti-doping is far less than the present study, and hence the detection rate will be lower.