A top anti-doping official has allayed fears over a new generation of "super EPO" drugs being used in sport.
Rabin is confident of winning the battle against EPO
Erythropoietin is a blood-boosting hormone used to improve stamina in endurance events, and drug companies are currently developing new versions.
But World Anti-Doping Agency science director Olivier Rabin, claimed Wada is well prepared for the new drugs.
He told BBC Radio Five Live: "We've been tracking them, and we're confident we can detect these new forms of EPO."
Also speaking to Five Live ahead of a scientific conference in Italy, German expert Professor Wolfgang Jelkman warned "super EPOs" will be far more potent and could prove a major headache for anti-doping agencies.
He said: "They have been developed for the benefit of patients because drugs with a long half-life would need to be given less frequently to them.
"But one of the problems we have to expect is sportsmen would use combinations of these different drugs, and then it would be very difficult to detect."
Michele Verroken, the former head of anti-doping at UK Sport, shares Prof Jelkman's concerns.
She told Five Live: "There is pressure on the EPO test and Wada have had to come out and state that they have every confidence that the EPO test is valid.
"Well, that was for the previous generation of drugs, now of course we've got a new generation, and that's no doubt going to raise questions again."
But Wada's Rabin added: "We've been working on those EPOs, and we've been able to test even recently some of the new forms in our anti doping laboratory."