Posted: 03/08/2015 at 09:55
Just for information;
I have spent some time looking into blood doping (academic interest only; honest). EPO is a hormone that occurs naturally in a human body in response to low oxygen levels. It was discovered in the early 20th Century and was available to 'use' but only from 'human' sources.
In the early '90's it was synthesized (created in a laboratory) and if you read Laurent Fignon's autobiography he seems to suggest that it was used from the mid '90's by cyclists. He says that he suddenly found he could not keep up with back-markers who seemed to be hardly trying, with talk in the bunch of, 'undetectable drugs'.
At the time it was impossible to test people for artificial EPO, particularly as you would have to be tested within 24 hours of taking the drug. At the time the authorities had to admit defeat and limit the use of EPO by saying that athletes with more than 50% red blood cells in their blood must 'rest' for two weeks for 'health reasons' it is thought that many cyclists have died as a result of their blood being too thick, causing blood clots.
This is still the case; but...
The blood passport allows testers to look at the composition of blood. Blood cells only 'live' for a fixed amount of time and 'grow old'. Someone who lives in one place will have a very consistent number of young and old cells. However if you take EPO you will have lots of young cells. If you take a blood transfusion you will have lots of old cells.
Comparing an athletes values with 'normal' values will provide evidence of artificial doping. This is now state of the art testing. But athletes can still boost their values naturally and of course they tend not to stay in one place or in particular 'altitude'.
Or if your Doctor messes up you could have two different blood groups! (Tyler Hamilton)