Erythropoietin (EPO)
Erythropoietin—more commonly known as EPO—is a type of blood doping that can help improve an athlete's endurance.
Its use in competitive sport was first brought to the public's attention during the 1998 Tour de France, where the entire Festina team was disqualified after several hundred doses of EPO and other doping products were found in the team car. EPO was once again linked with the event following Lance Armstrong’s admissions in 2012 of EPO use throughout his seven tour victories. Other sports associated with EPO use include boxing (Shane Mosley, 2003), 50km walk (Alex Schwazer, 2012) and athletics (Rashid Jacobs, 2008).
Produced naturally by the kidneys, EPO is also available as a pharmaceutical. EPO stimulates the production of red blood cells in bone marrow and regulates the concentration of red blood cells and haemoglobin in the blood. This is useful for athletes, since red blood cells shuttle oxygen to the cells, including muscle cells, enabling them to operate more effectively.
EPO is a peptide hormone and can be produced synthetically using recombinant DNA technology. By injecting EPO, athletes aim to increase the number of red blood cells and, consequently, their aerobic capacity.
If EPO levels are too high the body will produce too many red blood cells which can thicken the blood, leading to clotting, heart attack and stroke. Repeated doses of EPO can also stimulate the development of antibodies directed against EPO, which can result in anaemia. The long-term health risks of sustained EPO use are still unclear.
An approved test for EPO was first introduced at the Sydney 2000 Olympic Games. The test used a combination of urine testing, which would identify the presence of EPO (direct test) and blood testing, which would show the residual ‘footprints’ of EPO drug use over time (indirect test). This was the first time blood was used for drug testing.
Methods such as isoelectric focusing, which is the separation of proteins based on their electrical charge, and sodium dodecyl sulfate polyacrylamide gel electrophoresis, which is the separation of proteins based on their size, are used to detect EPO.
Since 2002, EPO tests in the United States were undertaken using only urine; however, in recent years the joint testing methods, such as direct EPO testing in urine and use of indirect markers in blood tests as part of the Athlete Biological Passport have been used to help identify the use of newly-developed erythropoiesis stimulating agents.
A new testing technique for EPO is also in the pipeline. Researchers are working on a detection method that will look for the effects of EPO in the body’s cellular anatomy as opposed to its presence in urine or blood. In essence the new test will look for genetic expressions which prove that EPO has been used. If the new test proves accurate and viable, it will be almost impossible to use EPO without detection.