Evidence that the Biological Passport is effective, summary version

21 Mar 2011 Posted by

The Biological Passport system has been criticized for being ineffective in the fight against doping. However, this is only when judged according to how many cyclists it has actually caught. That is only part of the question – the real test is whether it is effective enough to alter doping behaviour, possibly WITHOUT actually producing a slew of positive tests. And the answer to this question is a definite “yes”.

The graph below provides some evidence that this is the case. The results are explained briefly beneath the graph.

Percentage of blood samples measured in professional cycling that had UNUSUAL reticulocyte percentages. Source: Zorzoli & Rossi, 2010
Percentage of blood samples measured in professional cycling that had UNUSUAL reticulocyte percentages. Source: Zorzoli & Rossi, 2010

The graph shows the percentage of blood samples measured in professional cycling that had UNUSUAL reticulocyte percentages. Bear in mind that:

  • A ‘normal’ or physiological range for reticulocyte percent is 0.5% to 1.5%. Anything outside these is suggestive of doping
  • A HIGH reticulocyte percentage indicates that there are more immature RBC, and this happens because of removal of blood or the use of EPO, which both stimulate RBC formation
  • A LOW reticulocyte percentage indicates that there are fewer immature red blood cells because red blood cell production has been switched off – this happens after the infusion of RBC, or blood doping

Clearly, the introduction of the EPO test (red line) and the Biological Passport (blue line) change the balance of reticulocytes. First, EPO testing shifted abnormalities from high reticulocyte % to low reticulocyte % (suggesting a shift from EPO use to blood doping), and now the Biological Passport has reduced the overall percentage of abnormal samples dramatically.

There is no doubt that doping still occurs, but what this result suggests is that the ABP has been effective at bringing down the overall level of blood doping and EPO use. It has changed behaviour. The end result is a more even playing field, giving non-doped cyclists more of a chance.

For more on this, including a link between the above physiological changes suggesting less doping and performances in the Tour de France, read the related articles, below.

Ross

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