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The Explainer: The biological passport revisited

What does the passport do? How does it work? What are its limitations? Can athletes manipulate it?

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Hi Charles,
I appreciate your articles in VeloNews … very informative as well as being entertaining.

Somebody's earned a long vacation. Arrivederci, Franco.
Pellizotti has earned a long vacation. Arrivederci, Franco. He says he won't be back. Imagine our dismay. | Liquigas file photo

Would you please write about the biological passport? I think there is a lot of confusion and misconception about it as evidenced by readers’ comments following recent VN articles pertaining to Contador and Pellizotti.

What does the passport do? How does it work? What are its limitations? Can athletes manipulate it? Seems like the passport could be “managed” by those with the means to do so and prove to be relatively meaningless. And what about the impact of natural body reactions to the stress of racing, training, etc. that have been questioned? I’d really appreciate some insight on this.

I look forward to your thoughts and analysis in the Explainer. Thanks,

Dear Lew,
I did touch on the biological passport back in an earlier Explainer column, originally posted in May of last year. That column might answer some of your basic questions about the structure of the program, but in light of the recent Pellizotti decision, it might be time to take another look.

As you know, Franco Pellizotti and Pietro Caucchioli had both appealed suspensions that had been based on data acquired and analyzed as part of the UCI’s Biological Passport program. Pellizotti’s challenge had initially succeeded, when an Italian National Olympic Committee (CONI) doping panel ruled in October that the evidence garnered through analysis of his samples was insufficient to warrant a suspension. Interestingly, CONI found that adequate evidence did exist in Caucchioli’s case and ordered that he be suspended for two years.

Both cases were appealed; Pellizotti’s by the UCI and Caucchioli’s by the rider himself. On Tuesday, March 8, the International Court of Arbitration for Sport (CAS) ruled against both riders, finding that the aberrant readings found through the biological passport program did, indeed, provide sufficient evidence to warrant suspensions. According to CAS, the full text of the decision won’t be released for another three or four weeks, but it should bolster the UCI’s enforcement efforts and be a cause for concern for another rider challenging the Passport, namely former Ag2r rider, Tadej Valjavec.

On the eve of the 2010 Giro d’Italia, the UCI notified his team that Valjavec’s blood profile showed signs of manipulation and recommended his suspension. He was pulled from the team’s Giro roster and the case was considered by Slovenian cycling federation panel in July. As in Pellizotti’s case, the panel found the evidence to be insufficient and cleared him to ride again. And again, as in Pellizotti, the UCI appealed. A decision is pending in that case. Valjavec, who has since left Ag2r and is now riding for the Slovenian Zheroquadro Radenska squad, says he remains confident that he will be cleared. Despite the brave face, he should be worried, though, since his case essentially mirrored that of Pellizotti and that ruling will be considered by CAS when rendering a decision in the Valjavec case.

As I said, the full rulings in both Caucchioli and Pellizotti aren’t yet available, but the two decisions have to represent a huge boost for advocates of the biological passport program, since CAS appears to have reaffirmed the admissibility of such indirect evidence of doping and manipulation.

Is it perfect?

There have been some recent concerns raised about the accuracy of the Passport program, not necessarily pertaining to the risk of false “positives,” – as Caucchioli, Pellizotti and Valjavec – argued, but rather the risk of false “negatives” posed by those capable of employing sophisticated methods to avoid detection.

Most notably, Floyd Landis pointed to more subtle means of enhancing performance, that included “micro-dosing” EPO and careful use of a rider’s own stored blood (autologous blood doping). The combination of methods essentially masks some of the indicators used to detect manipulation. One of those is regular monitoring of reticulocytes – new red blood cells. That combination of techniques – small doses of EPO and autologous blood doping – might bring that key indicator to within “normal” range.

How does that work? At this point in time, the most effective means of detecting autologous blood doping is to track the percentage of reticulocytes in blood samples. Assuming neither of us is doping, our blood samples should show reticulocyte populations between 0.5- and 1.5-percent. The reinjection of stored blood should throw that percentage off. The nine-member biological passport panel assembled by the UCI relies, among other indicators, on something known as the “stimulation index.” That index represents a statistical analysis of the ratio of hemoglobin to reticulocytes. (The formula is HB(g/l) minus 60 times the square root of the percentage of reticulocytes, in case the math-inclined among us are wondering.) Again, assuming that neither of us is doping, our index scores should fall to within the range of about 85-95. Eyebrows become raised when riders’ scores start coming in at 125 or 130. It’s my understanding that a score of 133 or above is considered irrefutable evidence of manipulation.

So, to keep that score to within normal ranges, a particularly savvy doper will inject small doses of EPO to stimulate the production of more red blood cell production, which, of course, first appear as reticulocytes.

Now you might ask if the injection of EPO could be detectable. It is, but the window of opportunity is quite limited, using the now-10-year-old urine test for EPO. Following the manufacturer’s recommended dose of EPO, the isoforms produced by recombinant erythropoietin should show up for about three or four days after the initial injection. But, if a doper uses tiny doses – and injects intravenously, as opposed to the more common subcutaneous method – those isoforms would drop to normal ranges within just a few hours. So, the result is that a relatively sophisticated doper might be carefully monitoring the very parameters used by the Blood Passport Panel and making subtle adjustments along the way to escape detection.

Riccò hasn't been on a ProTour team since the '08 Tour.
Ricardo "the Refrigerator" Riccò: Poster boy for the do-not-try-this-at-home campaign.

Those caught in the net – Caucchioli, Pellizotti and Valjavec – may have simply made mistakes and been caught up after allowing one or more of their parameters to slip into the suspicious zones. Obviously, the methods would require a level of medical sophistication that should be beyond that of most individual riders. It’s an indication that if riders are doping ─ and getting away with it ─ they’re probably doing it with some serious (and expensive) help. Of course, there are some who try these methods at home, without medical supervision and there are a number of major risks involved that transcend mere detection. If you have doubts that you should not be trying this at home, I remind you of our old friend Ricardo Riccò, who nearly died after allegedly reinjecting his own blood that he had been storing in his refrigerator … you know, right next to that nice prosciutto di Parma.

The biological passport program examines a wide spectrum of indicators and the stimulation index is just one of many reviewed by the panel. As new methods — and combinations of old methods — are employed, the panel does have the ability to respond and examine blood and urine samples in new ways.

As we may have learned from Alberto Contador’s recent positive for minute amounts of clenbuterol, labs might be examining other data and looking for direct indicators of doping, like the presence of plasticizers in blood. That, of course, will prompt dopers to adopt their own new methods (glass transfusion bottles, anyone?), which in turn will trigger new tests and detection techniques. While it is far from perfect, the structure of the biological passport program does offer those involved in the fight against doping in sport a high degree of flexibility to respond quickly if new information comes to light.

What the Caucchioli and Pellizotti decisions represent is that CAS is at least willing to examine the resulting evidence. That’s a big step in the right direction. When the decisions in Caucchioli and Pellizotti are released in their entirety, it will be worth taking a careful look at what those rulings mean in terms of the standards of evidence CAS used in affirming those suspensions.

“The Explainer” is a regular feature on If you have a question feel free to send your query to and we’ll take a stab at answering. Not all letters will be published and some questions may be combined with those of other readers. Please include your full name and hometown.