Recombinant Human EPO (rhEPO) became commercially available in the late 1980s for treatment of anaemias related to kidney failure, cancer and AIDS. RhEPO accelerates the erythropoiesis and increase the amount of red blood cells (RBC) in human circulation, and thereby oxygen delivery to the body’s tissues. It was soon discovered that it also could be used in healthy athletes as a doping agent in endurance sports, as oxygen delivery to the muscles is the main performance limiting factor here.
RhEPO was banned by the International Olympic Committee (IOC) in 1990, but an effective test was not available until the year 2000. During the 1990s use of rhEPO and its analogues were quite prevalent in sports such as cycling, track & field and cross-country skiing. After the effective test was implemented during the 2000 Olympic Games in Sydney, Australia we have had quite a few high profile cases including skiers, runners and cyclists.
RhEPO is made from Chinese hamster ovary cells (CHO) and has a different glycocylation pattern than endogenous human EPO. The effective test relies on separating these isoforms by Isoelectric Focusing (IEF) because of their different isoelectric properties, with endogenous EPO being more acidic than rhEPO. An other form called Darbepoetin α has become available at a later stage and is also detectable by the same procedure, as this is more acidic than endogenous EPO. The main challenge to detect use is that the detection window for the agent is only about a week after its last administration.2