In addition to prohibited substances, the Prohibited List also specifies prohibited methods. This includes the manipulation of blood and blood components as well as the administration of synthetic blood substitutes such as emulsions of perfluorocarbons. All of these methods are prohibited because they improve the body's oxygen supply.

The improvement of endurance performance by transferring blood of another person into the circulation was first described in 1947. At the time, the method was aimed at improving the performance of pilots who were challenged by oxygen deficiency at high altitude. In sport, the manipulation of blood by homologous or autologous transfusion made its appearance in the 1980s and has been officially prohibited since 1985.

EPO versus blood doping

In the 1990s, the method of blood doping made way for the substance erythropoietin (EPO). Doping with EPO has similar effects as blood doping, but it is much easier to administer and involves a lower health risk. Since the year 2000, when EPO became directly detectable in urine, the use of blood doping has experienced a strong resurgence. Whereas doping with homologous blood is readily detectable, there is still no direct method to detect autologous doping. As a consequence, athletes in critical (endurance) sports are increasingly subjected to long-term blood profiling (Athlete's Biological Passport), which may provide evidence of blood manipulation.

Haematocrit

The total volume of blood in the human body ranges between five and six litres (70–80 ml per kg body weight). Blood consists of approx. 44% corpuscular elements and approx. 55% plasma. The rest (approx. 1%) is made up of hormones, dissolved gases, nutrients (sugar, fat and vitamins) and metabolites (e.g. urea and uric acid). Erythrocytes make up approx. 96% of the corpuscular elements of blood. The rest consists of white blood cells (leukocytes) and blood platelets (thrombocytes). The proportion of corpuscular elements in the blood volume is called haematocrit. Normal human blood contains approx. 47% corpuscular elements in men and approx. 42% in women.

For autologous doping, an athlete has an amount of blood removed from his body several weeks before a competition. From this blood, the red blood cells (erythrocytes) are removed and stored at a low temperature. In the meantime, the body compensates the loss of blood by producing new erythrocytes. Shortly before or during the competition, the stored erythrocyte concentrate is returned (transfused) to the athlete's body. This procedure increases the number of red blood cells that transport oxygen. The oxygen supply of the musculature is improved and performance endurance is increased.

In homologous doping, the erythrocyte concentrate of a donor is used, exactly the same method as for blood transfusions to patients with anaemia. Instead of traditional blood transfusions, synthetically manufactured products can also be used. These molecules cause the organism to increase its oxygen uptake, oxygen transport or oxygen release - depending on the type of molecule.

Stored autologous or homologous blood is transfused before or during a competition.

The number of red blood cells increases and the supply of oxygen to the muscles is improved.

⬆ Oxygen supply

Risk of death caused by an excessive haematocrit level

Blood doping and the use of synthetically produced (recombinant) EPO increase the number of red blood cells. An increase in haematocrit to a level around 60 % or more, whether in this unnatural way or by a natural process (by dehydration = water deficiency), entails serious health risks. The flow properties of the blood deteriorate markedly, leading to a greater likelihood of thromboses (blood clots) and embolism (a clot obstructing a blood vessel) and, in the worst case, to death.

Russian roulette due to improper handling of banked blood

Several cases have been documented where athletes incurred serious health risks because the blood had been improperly collected, stored, transported or transfused. This can lead to life-threatening sepsis (blood poisoning). With homologous blood doping, additional severe complications are possible. First, disease causing agents carried by the donor, such as the hepatitis virus or HIV, may be transmitted. Second, a blood incompatibility reaction may be triggered and cause an allergic shock. This state of shock may lead to death.

Blood doping improves endurance performance and is therefore used in the classical endurance disciplines, particularly in cycling and cross-country skiing.

Direct detection of homologous doping

Today, the detection of homologous doping is fairly simple. The first and best-known case involved the US-American professional cyclist Tyler Hamilton. During his full confession in the Lance Armstrong affair, he put on record that he had actually intended to dope with his own blood, but this did not happen because the blood bags of different athletes had been mixed up.

Indirect detection of autologous doping

As no direct detection method for autologous doping is available yet, most cases of autologous doping are discovered through police investigations and confessions. Moreover, athletes in critical (endurance) sports are increasingly subjected to long-term blood profiling (Athlete's Biological Passport) which may provide evidence of blood manipulation.