Blood doping by cobalt. Should we measure cobalt in athletes?

Cobalt, a naturally-occurring element with properties similar to those of iron and nickel, induces a marked and stable polycythemic response through a more efficient transcription of the erythropoietin gene.Although little information is available so far on cobalt metabolism, reference value ranges or supplementation in athletes, there is emerging evidence that cobalt is used as a supplement and increased serum concentrations are occasionally observed in athletes. Therefore, given the athlete's connatural inclination to experiment with innovative, unfair and potentially unhealthy doping techniques, cobalt administration might soon become the most suited complement or surrogate for erythropoiesis-stimulating substances. Nevertheless, cobalt administration is not free from unsafe consequences, which involve toxic effects on heart, liver, kidney, thyroid and cancer promotion.Cobalt is easily purchasable, inexpensive and not currently comprehended within the World Anti-Doping Agency prohibited list. Moreover, available techniques for measuring whole blood, serum, plasma or urinary cobalt involve analytic approaches which are currently not practical for antidoping laboratories. Thus more research on cobalt metabolism in athletes is compelling, along with implementation of effective strategies to unmask this potentially deleterious doping practiceErgogenic drugs are substances commonly used to enhance the athletic performance and include illicit drugs as well as a variety of compounds that are marketed as nutritional supplements. Although such drugs have been widely used by professional and elite athletes for centuries, research indicates that in recent years competitive athletes are increasingly experiencing with illicit compounds to improve both appearance and athletic abilities. Blood doping consists on techniques administered for non-medical reasons to healthy athletes to improve the blood oxygen carrying capacity, increasing oxygen deliver to the muscles, particularl