As athletes experiment with drugs that can help give them an edge over their competition, they tweak their strategies to try to evade detection. Meanwhile, anti-doping researchers are continuously developing assays and other methods that are more sensitive to low levels of doping agents that accumulate in urine or blood, or that extend the detection window to secure a positive test from a cheating athlete.
For athletes who want to cheat, the most attractive substances are those that are already found in the body. Besides EPO, these include growth hormone, steroids such as testosterone, and blood transfusions. Because exogenous and endogenous biomolecules can be challenging to distinguish and because there is a wide range of “normal” levels for these compounds and their associated metabolites, these agents present a particular challenge to anti-doping watchdogs.
…[T]he World Anti-Doping Agency (WADA) introduced the Athlete Biological Passport (ABP) to track biomarkers in individual athletes over the long term. In 2009, WADA formally launched the ABP’s blood module, which tracks markers of blood doping in circulation. Levels of hemoglobin, red blood cells, and other blood-borne markers of EPO and whole-blood doping are monitored. In urine samples, peptide hormones, including growth hormone, are also tracked.
Read full, original post: The Race to Nab Cheating Athletes