Identification of blood erythroid markers useful in revealing erythropoietin abuse in athletes

Recombinant human erythropoietin (rEpo) is being used with increasing frequ ency by endurance athletes to improve aerobic potential. Although rEpo admi nistration has been banned by the International Olympic Committee, no metho ds are available to unequivocally detect its abuse in sports. Prompted by t hese considerations, we evaluated the main hematological and biochemical mo difications measured in the blood of 18 volunteers upon rEpo administration . Different rEpo regimens, iron, folic acid, and vitamin B 12 administratio n did not significantly modify the percentage increase in hematocrit. Howev er, a significant decrease in circulating ferritin (fr) and an increase in the soluble transferrin receptor (sTfr) were not found in athletes receivin g low (30 IU/kg) doses of rEpo. Thus, an increase in the sTfr/fr ratio cann ot be used as an indicator of rEpo abuse, at least when the hormone is admi nistered at low concentrations. In contrast, the amounts of beta -globin mR NA detected by quantitative competitive (RT)-PCR in whole blood samples sig nificantly increased above the threshold levels in all of the treatments in vestigated. Taken together, these data suggest that hematocrit value, retic ulocyte count, soluble transferrin receptor content, and concentration of b eta -globin mRNA, when included in a new multiparametric formula, can detec t rEpo abuse in 57.5% of the samples examined with a confidence interval of 99.99%. Thus, the method reported in this paper could significantly improv e the tests currently available, which in similar experiments allowed the d etection of rEpo abuse in only 7.6% of the samples examined. (C) 2001 Acade mic Press.