surface of blood cells, the method can determine whether blood from more than one person is present in an athlete's circulation. the test utilizes 12 antisera directed against the blood group antigens, obtained from donor plasma. the antigens are labeled with secondary antibodies, which are conjugated with phycoerythrin to label igg or igm-coated rbcs and enhance the detection by flow cytometry the flow cytometry is able to detect minor variance in blood group antigens. the assessment was able to distinguish the blood of subjects who had earlier received at least one unit of allogeneic blood. this technique is able to detect small (<5%) populations of cells that are antigenically distinct from an individual's own rbcs. detection for autologous blood doping autologous blood doping detection is done indirectly via co rebreathing technique to measure the nonphysiologic increases in hb mass. the principle of co rebreathing method used currently requires an o2-co gas mixture inhalation for about 10-15mins. by measuring the difference in carboxyhemoglobin concentration (hbco) before and after rebreathing, the volume of co and the binding capacity of hb for co ( 1.39ml g-1), total hb mass can be calculated. this detection method is problematic for an athlete as it is not desirable to breathe in co shortly before a competition, which may potentially affect their performances. detection of blood hemoglobin-based oxygen carrier detection method for hemoglobin-based oxygen carriers (i.e. oxyglobulin) is done in four separate steps. step one involves the elimination of abundance proteins in the blood samples by immunodepletion (i.e. proteo prep 20 plasma immunodepletion kit). this process ensures that other proteins (i.e. albumin and immunoglobulin) do not interfere with capillary electrophoresis (ce) separation by changing the ionization. second step, ce separation is done under certain condition, in this case background electrolyte consisting of ammonium formate (75mm at ph 9.5) in order to provide sufficient resolution between hboc and hb. third step, uv/vis detection was performed at 415 nm to selectively detect hboc and hb. fourth step, time-of-flight or mass spectrometer allowed increased accuracy in selectivity between hemoproteins and other proteins and definite determination of hboc uptake. the detection limits for ce-uv/vis at 415 nm and ce-esi-tof/ms results to be 0.20 and 0.45g/dl for plasma respectively. detection of cobalt concentration by utilizing the biokinetic model cobalt can be detected by laboratory blood analysis if the intake amount is greater than 400 μg per day. as the whole blood concentration is greater than 1 μg/l and the urinary concentration is greater than 10 μg/l after at least 10 days of administration. the dose, which increases the red blood cell production to approximately 16%-21%, is about 68 mg co per day for at least 10 days of oral administration. the predicted whole blood concentration of cobalt exceeds 200 μg/l two hours after the last intake and the average urine concentrations of cobalt exceed 3000 μg/l within 24 hours of intake. a study was carried out where 23 subjects were to take 900 μg per day in the form of cocl2 for 10 days. the model predictions were then compared to the study. the result shows that the model prediction for blood and urine are between the median concentration of the male and female groups, which indicate the model predictions sufficiently represent the test population as a whole. military use as early as 1947, military research scientists were studying ways to increase fighter pilots' tolerance for hypoxia at high altitude. in one such study, red blood cells were transfused into ten males at the us naval research facility, resulting in increased oxygen capacity. in 1993, u.s. special forces commanders at fort bragg started experimenting with blood doping, also known as blood loading. special forces operators would provide two units of whole blood, from which red blood cells would be extracted, concentrated, and stored under cold temperatures. 24 hours before a mission or battle, a small amount of red blood cells would be infused back into the soldier. military scientists believe that the procedure increases the soldiers' endurance and alertness because of the increase in the blood's capability to carry oxygen. in 1998, the australian defence forces approved this technique for the special air service regiment. senior nutritionist at the australian defence science and technology organisation chris forbes-ewan is quoted as saying that, unlike in sport, "all's fair in love and war." "what we are trying to gain is an advantage over any potential adversary," forbes-ewan said. in this study, over 50 performance-enhancing drugs and techniques were rejected. the six that were approved are caffeine, ephedrine, energy drinks, modafinil, creatine, and blood-loading. notable blood doping cases kaarlo maaninka (208), the subject of the first known blood doping case, in the 1980 summer olympics 5,000 m race. blood doping started in the late 1960s but was not outlawed until 1986. while it was still legal, it was commonly used by middle and long-distance runners. the first known case of blood doping occurred at the 1980 summer olympics in moscow as kaarlo maaninka was transfused with two pints of blood before winning medals in the 5 and 10 kilometer track races, though this was not against the rules at the time. cyclist joop zoetemelk admitted to receiving blood transfusions during the 1976 tour de france, where he finished second, although he claimed that these were intended to treat his anaemia rather than enhance his performance. in the same year cyclist francesco moser used blood transfusions to prepare for his successful attempt to break the hour record. "blood doping" was banned by the international olympic committee (ioc) in 1985, though no test existed for it at the time. cyclist niklas axelsson tested positive for epo in 2000. cyclist tyler hamilton failed a fluorescent-activated cell sorting test for detecting homologous blood transfusions during the 2004 olympics. he was allowed to keep his gold medal because the processing of his sample precluded conducting a second, confirmatory test. he appealed a second positive test for homologous transfusion from the 2004 vuelta a españa to the international court of arbitration for sport but his appeal was denied. hamilton's lawyers proposed hamilton may be a genetic chimera or have had a 'vanishing twin' to explain the presence of red blood cells from more than one person. while theoretically possible, these explanations were ruled to be of "negligible probability". tour de france rider alexander vinokourov, of the astana team, tested positive for two different blood cell populations and thus for homologous transfusion, according to various news reports on july 24, 2007. vinokourov was tested after his victory in the 13th stage time trial of the tour on july 21, 2007. a doping test is not considered to be positive until a second sample is tested to confirm the first. vinokourov's b sample has now tested positive, and he faces a possible suspension of two years and a fine equal to one year's salary. he also tested positive after stage 15. vinokourov's teammate andrej kashechkin also tested positive for homologous blood doping on august 1, 2007, just a few days after the conclusion of the 2007 tour de france (a race that had been dominated by doping scandals). his team withdrew after the revelation that vinokourov had doped. according to russian investigators, 19-year-old new york rangers prospect and russian hockey player alexei cherepanov was engaged in blood doping for several months before he died on october 13, 2008, after collapsing on the bench during a game in russia. he also had myocarditis. the german speed skater and five-fold olympic gold medalist claudia pechstein was banned for two years in 2009 for alleged blood doping, based on irregular levels of reticulocytes in her blood and the assumption that these levels were always highest during competitions. her mean reticulocyte count over the ten years from 2000 to 2009 was 2.1% during top events like olympic games and during world championships. at world cup races the mean reticulocyte was 1.9% and during training phases 2.0%. the court of arbitration for sport confirmed the ban in november 2009 in stating: "...once the possibility of a blood disease has been safely excluded...". in september 2010, the swiss federal supreme court rejected the athlete's appeal, stating that pechstein's inherited blood anomaly had been known before ("die vererbte blutanomalie bekannt gewesen sei"). on may 20, 2011, tyler hamilton turned in his 2004 olympic gold medal to the u.s. anti-doping agency after admitting to doping in a 60 minutes interview. on august 23, 2012, lance armstrong was stripped of his seven tour de france titles and banned for life by cycling's governing body following a report from the u.s. anti-doping agency that accused him of leading a doping program during his cycling career. he later admitted to using banned substances including blood doping with transfusions and epo in an interview with oprah winfrey on january 17, 2013. in june 2014, ufc fighter chael sonnen tested positive for epo. one month later, another ufc fighter, ali bagautinov also tested positive for epo. in february 2018, bahraini steeplechase and 3000m steeplechase world record holder ruth jebet tested positive for epo and in the 4th of march, she was suspended for 4 years. adverse effects the simple act of increasing the number of red blood cells in blood may be associated with hyperviscosity syndrome which is characterized by increased blood viscosity and decreased cardiac output and blood flow velocity which results in the reduction of peripheral oxygen delivery. for instance, an overdose of epo can thicken blood into a highly viscous and artery-clogging sludge. this increases the chances of heart attack, stroke, phlebitis, and pulmonary embolism, which has been seen in cases where there is too much blood reintroduced into the blood stream. because blood doping increases the volume of red blood cells, it effectively introduces a condition called polycythemia, a blood disorder that has known adverse outcomes such as heart attacks or strokes. blood contamination during preparation or storage is another issue. contamination was seen in 1 in every 500,000 transfusions of red blood cells in 2002. blood contamination can lead to sepsis or an infection that affects the whole body. certain medications used to increase red blood cells can reduce liver function and lead to liver failure, pituitary problems, and increases in cholesterol levels.