Blood Doping - Methods

Methods

The term blood doping originally meant doping with blood, i.e. the transfusion of red blood cells. Red blood cells are uniquely suited to this process because they can be concentrated, frozen and later thawed with little loss of viability or activity. There are two possible types of transfusion: homologous and autologous. In a homologous transfusion, red blood cells from a compatible donor are harvested, concentrated and then transfused into the athlete’s circulation prior to endurance competitions. In an autologous transfusion, the athlete's own red blood cells are harvested well in advance of competition and then re-introduced before a critical event. For some time after the harvesting the athlete may be anemic.

Both types of transfusion can be dangerous because of the risk of infection and the potential toxicity of improperly stored blood. Homologous transfusions present the additional risks of communication of infectious diseases and the possibility of a transfusion reaction. From a logistical standpoint, either type of transfusion requires the athlete to surreptitiously transport frozen red blood cells, thaw and re-infuse them in a non-clinical setting and then dispose of the medical paraphernalia.

In the late 1980s, an advance in medicine led to an entirely new form of blood doping involving the hormone erythropoietin (EPO). EPO is a naturally occurring hormone growth factor that stimulates the formation of red blood cells. Recombinant DNA technology made it possible to produce EPO economically on a large scale and it was approved in US and Europe as a pharmaceutical product for the treatment of anemia resulting from renal failure or cancer chemotherapy. Easily injected under the skin, pharmaceutical EPO can boost hematocrit for six to twenty-four weeks, or longer.

EPO is not free of health hazards: excessive use of the hormone can raise hematocrit above 70% which can cause polycythemia, a condition wherein the level of red blood cells in the blood is abnormally high. This causes the blood to be more viscous than normal, a condition that strains the heart. Some elite athletes who died of heart failure—usually during sleep, when heart rate is naturally low—were found to have unnaturally high red blood cell concentrations in their blood.