LAUSANNE, Switzerland - Anti-doping laboratories are working on a test to detect a powder used to destroy traces of the performance-enhancer EPO in urine samples.

Martial Saugy, the head of the Swiss anti-doping laboratory, said there have been suspicious tests during the last year in which no traces of EPO — or erythropoietin — were found in athlete’s urine, not even natural EPO produced in the kidney.

Researchers suspect cheats are using a substance called protease — sometimes used in stain removers — to wipe out traces of EPO in their urine.

“There has been a significant increase in the number of samples in which there is no EPO detected at all, leading us to believe they are being manipulated,” Saugy said Sunday. “We have no proof so far but there are indications that a powder exists.

“It can happen that people who excrete less EPO than others have a result where there is no EPO, but it is unusual. And over this last year we’ve seen some suspicious cases of EPO-free urine samples, where we did not understand why suddenly it was undetectable.”

Scientists are now seeking a test to detect the presence of protease in urine, which is proving tricky.

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“We’re working in biology and in biology these products deteriorate very quickly,” he said. “In urine it (protease) is a product which will be invisible after a certain time. It’s not complicated but we still need to work on it.”

Protease is cheap, readily available, and the cheating process is simple.

Cheaters could slip the powder into a urine sample by putting a hand in their pocket where some protease is stashed, then urinating on their fingers. Very little powder is needed to break down proteins — including EPO — in urine in the space of a few minutes.