Most blood doping techniques can be reliably detected by current anti-doping strategies. But Italian researchers have issued a warning about an alternative and dangerous technique, which is not yet banned and is virtually undetectable by anti-doping tests.

The purpose of blood doping is to boost the concentration of oxygen-carrying red cells in the blood with a view to enhancing athletic performance. Traditional doping methods include blood transfusion and the use of various substances designed to stimulate red blood cell production, technically known as erythropoeisis.

A newer technique involves inducing an apparent oxygen deficiency (hypoxia), which stimulates the body to increase erythropoiesis as a corrective reaction. Researchers have already suggested that gene therapy targeting the ‘hypoxia inducible factor pathway’ may in future be an alternative to traditional blood doping for athletes in search of a competitive edge.

Meanwhile, this effect can already be achieved by taking cobalt chloride, a compound traditionally used to treat anaemia, and which is a well- established chemical inducer of hypoxia-like responses, including erythropoiesis.

There’s no evidence as yet that cobalt chloride is being given to athletes as an ergogenic aid, report the researchers. ‘However, we cannot exclude the possibility that it may become an attractive alternative to traditional performance enhancing drugs.’

The main cause for concern is that cobalt can accumulate in the liver, kidneys and heart, leading to organ damage and dysfunction – even at a moderate dose of 33.3mg per kg of body weight.

‘Owing to the severe and often unpredictable side effects, cobalt chloride administration may turn out to be a serious concern for the sporting community and athletes’ health,’ conclude the researchers.

However, they point out that testing for cobalt during competition would involve a great deal of wasted effort since the compound is metabolised very rapidly and is eliminated from the body within 24 hours of ingestion.

Br J Sports Med 2005; 39; 872-873