عرف الرياضيون طريقة التنشيط بالدم Blood Doping عن طريق عملية نقل الدم Blood  transfusion  حيث بتم سحب ما بين 500–750 سم مكعب  من دم اللاعب ويحفظ في (بنك الدم) قبل أربعة أشهر من البطولة أو المنافسة ، وقبل بدء المبارة بأربع ساعات يعطي  اللاعب الدم ثانية  عن طريق الحقن بالوريد لرفع نسبة  الهيموجلوبين بالدم . و نقل خلايا الدم الحمراء للاعب لزيادة قدرة حمل الأكسجين في الدم. وهذه الوسيلة يصعب  أكتشافهاthumb|200px|Normal (a) and distorted Erythrocytes (b-d)إلا من خلال اعتراف المدرب أو اللاعبين أو كشف عملية نقل الدم.وهناك  هورمون الارثروبوتبين (EPO) erythropoetin الذي يعمل كمعزز لتكوين كريات الدم الحمراء وهذا الهورمون يفرز طبيعيا بالكلي لينشط النخاع العظمي لصنع هذه الكريات . وحاليا يصنع هذا الهورمون صناعيا  ويعطي في نقص افرازه بالكليتين . وهذا الهورمون يزيد من نسبة الهيموجلوبين بالدم مما يسبب تشبع الخلايا بالاوكسين. وهذه الوسيلة  تفيدعدائي المسافات الطويلة ولاعبي سباق الدراجات والسباحين لأن عضلاتهم  تستهلك كميات هائلة من الأكسجين الذي تحمله إليها  كريات الدم الحمراء أثناء المسابقات . لكن تأثيراته الجانبية  أنه قد يسبب اضطرابا في توازن كريات الدم الحمراء بالجسم .و سوء استخدام هورمونات (EPO ) قد يتسبب في ثخونة الدم بما يؤدي إلى الاصابة بالأزمات القلبية والسكتات الدماغية والوفاة في النهاية.

مصدر : 

'''Blood doping''' is the practice of boosting the number of red blood cells (RBCs) in the circulation in order to enhance athletic performance. Because they carry oxygen from the lungs to the muscles, more RBCs in the blood can improve an athlete’s aerobic capacity (VO<sub>2</sub> max) and endurance.

==Methods==
The term blood doping originally meant doping with blood, i.e. the transfusion of RBCs. RBCs 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 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 RBCs, 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 under the skin, pharmaceutical EPO can boost hematocrit for six weeks or longer. The use of EPO is now believed by many to be widespread in endurance sports. 

EPO is also not free of health hazards: excessive use of the hormone can cause polycythemia, a condition where the level of RBCs 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 RBC concentrations in their blood<ref></ref>.

===Detection of blood doping === 

A time-honored approach to the detection of doping is the random and often repeated search of athletes’ homes and team facilities for evidence of a banned substance or practice. Professional cyclists customarily submit to random drug testing and searches of their homes as an obligation of team membership and participation in the inject or infuse non-banned substances such as vitamin B or electrolytes, the possession of syringes or other medical equipment is not necessarily evidence of doping.

It has also been possible to link athletes to blood doping entirely through documentary evidence, even if no banned substance has been found and no athlete has failed a doping test. The Operación Puerto case is a recent example.

A more modern approach, which has been applied to blood doping with mixed success, is to test the blood or urine of an athlete for evidence of a banned substance or practice, usually EPO.  This approach requires a well-documented chain of custody of the sample and a test method that can be relied upon to be accurate and reproducible. Athletes have, in many cases, claimed that the sample taken from them was misidentified, improperly stored or inadequately tested.

Yet another detection strategy has been to regard any apparently unnatural population of RBCs as evidence of blood doping. RBC population in the blood is usually reported as hematocrit (HCT) or as the concentration of hemoglobin (Hb). HCT is the fraction of blood cells by volume that are RBCs. A normal HCT is 41-50% in adult men and 36-44% in adult women<ref></ref>. Hemoglobin (Hb) is the iron-containing protein that binds oxygen in RBCs. Normal Hb levels are 14-17 g/dL of blood in men and 12-15 g/dL in women. For most healthy persons the two measurements are in close agreement.

There are two ways in which HCT and Hb measurements can suggest that the blood sample has been taken from a doping athlete. The first is simply an unusually high value for both. The deciliter (g/dL). A few athletes naturally have high RBC concentrations (polycythemia), which they must demonstrate through a series of consistently high hematocrit and hemoglobin results over an extended period of time. 

A recent, more sophisticated method of analysis, which has not yet reached the level of an official standard, is to compare the numbers of mature and immature RBCs in an athlete's circulation.  If a high number of mature RBCs is not accompanied by a high number of immature RBCs--called reticulocytes--it suggests that the mature RBCs were artificially introduced by transfusion. EPO use can also lead to a similar RBC profile because a preponderance of mature RBCs tends to suppress the formation of reticulocytes. A measure known as the "stimulation index" or "off-score" has been proposed based on an equation involving hemoglobin and reticulocyte concentrations. A normal score is 85-95 and scores over 133 are considered evidence of doping. (The stimulation index is defined as Hb (g/L) minus sixty times the square root of the percentage of RBCs identified as reticulocytes.)

These threshold levels, and their specific numeric values are sources of controversy. Establishment of incorrect threshold values is one way that false positive test results can be produced by a doping control program.

===Detection of EPO use===

Some success has also been realized in applying a specific test to detect EPO use. An inherent problem, however, is that whereas pharmaceutical EPO may be undetectable in the circulation a few days after administration, its effects may persist for several weeks. In French national anti-doping laboratory (LNDD) and endorsed by the World Anti-Doping Agency (WADA) was introduced to detect pharmaceutical EPO by distinguishing it from the nearly identical natural hormone normally present in an athlete’s urine. The test method relies on scientific techniques known as gel electrophoresis and isoelectric focusing. Although the test has been widely applied, especially among cyclists and triathletes, it is controversial and its accuracy has been called into question. The principal criticism has been the ability of the test to distinguish pharmaceutical EPO from other proteins that may normally be present in the urine of an athlete after strenuous exercise.

The validity of a doping conviction based on the EPO test method was first challenged successfully by Belgian triathelete Rutger Beke. Beke was suspended from competition for 18 months in March 2005 by the Flemish Disciplinary Commission after a positive urine test for EPO in September 2004. In August 2005 the Commission reversed its decision and exonerated him based on scientific and medical information presented by Beke. He asserted that his sample had become degraded as a result of bacterial contamination and that the substance identified by the laboratory as pharmaceutical EPO was, in fact, an unrelated protein indistinguishable from pharmaceutical EPO in the test method. He claimed, therefore, that the test had produced a false positive result in his case.

In May various doping scandals at the 2007 Tour de France, including the suspension of Spanish cyclist, Iban Mayo.

===Detection of blood transfusions===
In the case of detecting blood transfusions, a test for detecting homologous blood transfusions (from a donor to a doping athlete) has been in use since 2000.  The test method is based on a technique known as fluorescent-activated cell sorting. By examining markers on the surface of blood cells, the method can determine whether blood from more than one person is present in an athlete’s circulation. 