italy_dopingEPO stands for erythropoietin, a glycoprotein hormone that controls erythropoiesis, or red cell blood production. Because of this property, exogenous EPO (also called erythropoiesis stimulating agent or ASA) is sought after by endurance athletes, such as cyclists and marathon runners, because it boosts aerobic power.

Marathon runner Deeja Youngquist tested positive for EPO during an out-of-competition screening prior to the 2004 US Olympic trials. The then 28-year-old Youngquist was penalized with a two-year-ban, which ended in December 2006.

Tour De France seven-time champ Lance Armstrong has been continually hounded by rumors of EPO use.

The testing for EPO has always been under scrutiny because of questions about its accuracy.  Exogenous EPO is almost identical to its natural counterpart so you cannot really be 100 percent sure if it’s injected or naturally occurring. Moreover, there are other two conditions that make testing for this prohibited compound problematic.

First, a test can only effectively detect EPO if it’s injected within six days of the use; beyond that it’s like you searching for a coin under murky water.

Second, some individuals have a natural higher percentage of RBCs, high enough to yield a positive test.