There are different modules to the ABP, e.g.,
hematological, steroidal & growth hormonal. Fluctuations in these markers allow for target testing - especially for OOC testing when dopers are more likely to be glowing. rEPO usage would influence the hematological module. Anabolic steroids, testosterone, SARMs, etc, usage would influence the steroid module. HGH, IGF-1, growth hormone peptides (GHRP-2), etc, would influence the growth hormone module.
However, the
hematological module of the ABP (and the first implementation of the ABP in 2009) was designed to detect blood transfusions which of course unlike rEPO is undetectable. In a nutshell, when a doper withdrawls blood for a later transfusion, Hct/Hgb
declines & RET%
increases. On the transfusion, the opposite occurs - Hct/Hgb
increases & RET%
declines. If enough blood samples are taken over time, then a distinct pattern can be seen particularly during the time leading up to & during competition, hence the blood "
anomalies" that we hear about when a doper is banned.
In terms of a ban, the anomalies must reach a certain
Off-Score &
99.9% specificity -
less than 1 in 1000 chance that the anomalies were
undoped & the result of physiological or medical condition (the UCI uses a panel of 3 anti-doping experts - usually MDs & PhDs with a background in hematology & sports medicine - to evaluate the any anomalies flagged in an athlete's passport).
One of the designers of the ABP & top anti-doping experts who has served on many panels of doping hearings is
Dr. Olaf Schumacher. Here's a paper of his that provides an excellent introduction to hematological module of the ABP. There's examples of what different fluctuations & influence on Hct/Hgb & RET% look like with EPO/ESA usage vs blood transfusions. There's one interesting example of what the fluctuations look like with a rider using transfusion during an actual Grand Tour:
scholar.google.com
Also, here's a interesting lecture by Schumacher on the ABP in relation to professional cycling (there are representatives from some top cycling teams in the audience):
View: https://youtu.be/m38WqCxEaLk?si=-Dk9eNiaT4aU772k
Here's a list of cyclists that have been banned for hematological anomalies in their ABP (not nearly as many as in athletics):
en.m.wikipedia.org
Now if really want to dive deep into this, here's the details of the UCI hearing on
Juan Cobo's anomalies case from several years ago when he was banned & stripped of his 2009
Vuelta Espana win (Schumacher was one of the 3 anti-doping experts on the panel):