Detection window of Darbepoetin-alpha following one single subcutaneous injection

The current official direct recombinant erythropoietin (rHuEPO) detection anti-doping test based on 1D isoelectric focusing (IEF) of urinary proteins was performed to determine the detection window of Darbepoietin-alpha when applying the positivity criteria established by the World Anti-Doping Agency (WADA).

Following WADA's positivity criteria, the IEF based urinary EPO test enabled to determine that the detection window after a single subcutaneous injection of Darbepoietin-alpha (40 microg of ARANESP injected) is close to 7 days, that is to say approximately two times more than for rHuEPO-beta (4000 IU of Recormon injected). The detection window can be different from one subject to another, because the actual positivity criteria take into consideration in someway the endogenous EPO production rate which differs enormously from one subject to another. That means, all subjects with a naturally elevated or stimulated EPO production rate (altitude training, hypoxic tent,...) have a reduced detection window for bone marrow stimulators such as Darbepoietin-alpha.

Darbepoietin-alpha has a much longer detection window in urine than any other available EPOs, which is a major disadvantage for illegal use in sports. The positivity criteria used up to now by all anti-doping laboratories are very conservative. Furthermore all athletes tested for rHuEPO are not equal regarding the actual test. For that reason, the criteria could be slightly adapted in the future, but further experiments are needed.