In an article in International Herald Tribune there is an interesting theory about hiding of EPO abuse. Scientists in laboratoriums in Switzerland work to develop a test that can prove a special powder used to destroy traces of the drug EPO (erythropoietin). In the past year there has been a significant increase in the number of tests showing no EPO at all. The scientists have the theory that the riders use a protease that can brake down proteins in the urine.

“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.” Said Martial Saugy, the head of the Swiss anti-doping laboratory, to International Herald Tribune.

Small amount of protease can remove EPO
It is possible to remove EPO from the urine by putting protease on their hands, then urinating on their fingers. Only a small amount of protease is needed to brake down all EPO in the urine.

This theory might explain why so relative few riders have delivered a positive EPO test compared to how many riders have been caught with an enhanced hematocrit.