The future of doping control in athletes - Issues related to blood sampling

When current antidoping programmes were developed, the most frequently used doping agents were xenobiotics, such as stimulants and anabolic steroids, that are readily detectable in urine with the use of gas chromatography and mass spectrometry. As control of traditional doping agents became effectiv e, some athletes turned to other means to improve performance, including bl ood doping and the application of recombinant peptide hormones such as eryt hropoietin and growth hormone. Doping with these agents is not easily detec ted in urine samples, and therefore new strategies must be developed as a s upplement to those already in use. Such strategies will probably include an alysing blood samples, as several of the most promising methods that are ab le to detect modern doping agents use blood as the analytical matrix. Non-autologous blood doping results in an admixture of self and foreign red blood cells that can be detected in a blood sample with the methods availa ble. Methods to indicate doping with erythropoietin include the indirect fi nding of an elevated level of soluble transferrin receptor in serum, or a d irect demonstration of a shift from the normal to an abnormal spectrum of e rythropoietin isoforms. To indicate doping with growth hormone, a set of se rum parameters including insulin growth factors and their binding proteins are under investigation as indirect evidence. A direct method using isotopi c differences between endogenous and recombinant growth hormones is being i nvestigated. A similar method has been established to detect the administra tion of testosterone esters. Several legal and ethical questions must be solved before blood sampling ca n become a part of routine doping control, but the major ethical question i s whether sport can continue as today without proper methods to detect many modem doping agents.