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How do biological passports work?

James Witts
20 Apr 2016

With news that the UCI has opened a bio passport case against Sergio Henao, we look back at the story, and the bio passport itself.

With news that the UCI has opened a biological passport case against Team Sky's Sergio Henao, and that he has been suspended from competition by his team, we take a look back at when the anomalies first surfaced, as well as scritinising how the biological passport actually works. 

This article first appeared in Cyclist in summer 2014.

‘We have strong monitoring and compliance on this team with full co-operation of riders and coaches. In our latest review, we had questions about Sergio’s control tests… We want to do the right thing and we want to be fair. It’s important not to jump to conclusions.’ The words of Team Sky boss Dave Brailsford after it came to light that their Colombian rider, Sergio Henao, had registered anomalous blood-test readings. Henao’s withdrawal from racing in 2014 lasted 10 weeks, in which time Team Sky’s own investigations came to the conclusion that Henao hadn’t succumbed to temptation. The episode highlighted not only the British team’s zero tolerance drug policy but also the apparent effectiveness of cycling’s anti-doping programme in 2014, which uses the Athlete Biological Passport (ABP) to track various biological markers that can reveal the effects of doping. A team testing their own athlete and publicly withdrawing him from racing? It’s certainly a far cry from Bruyneel, Armstrong and Motoman…

WADA and the facts

In 2012, the World Anti-Doping Agency (WADA) released drug-testing data across all sports for the first time. It was a comprehensive report, explaining how the authorities are battling the cheats. Highlights included: 267,645 samples were analysed in 2012; Los Angeles was the busiest laboratory in the world, analysing 41,240 tubes of blood and urine; 42 competitors were tested in the high-octane sport of bridge. 

As for cycling, its anti-doping programme put 20,624 samples under the microscope, 19,318 of which were urine and 1,306 of which were blood. Of those, 502 came back as showing an ‘atypical finding’ or ‘adverse analytical finding’, meaning the rider either had a case to answer or had been allowed medication via a ‘therapeutic use exemption’ (TUE), as per Chris Froome’s well-publicised prednisolone (steroid) use en route to winning the 2014 Tour de Romandie. But those WADA figures excluded the tests for cycling’s ABP, with the authorities taking a further 6,424 blood and urine samples, 4,352 of those out of competition. 

The ABP has been much trumpeted since its introduction in 2008, but how does it differ – and complement – existing testing methods? Over to Olivier Banuls, manager of the Cycling Anti-Doping Foundation (CADF), essentially an independent drug-testing arm of the UCI. ‘The difference between the old method of testing and the ABP is that the tests cover a period of time and look for the effects of the substance abuse rather than focusing on the actual substance itself,’ he says. ‘It means we can analyse whether there are any anomalous fluctuations in any of the indirect markers of drug abuse.’

Whereas traditional tests look directly at, for example, the level and type of erythropoietin (EPO) in urine, the ABP analyses biological markers of doping – responses and changes in the cyclist’s body that give a clear indication of doping. ‘The reason is that the traditional approach has limitations when an athlete may be using substances on an intermittent or low-dose basis,’ says Banuls. ‘The ABP is more reliable.’

In theory, the measurements taken cover three ‘modules’: haematological (blood doping), steroid abuse and manipulation of the endocrine system (hormone abuse, eg human growth hormone). Since the ABP’s launch in 2008, only the blood module had clear guidelines but, on 1st January 2014, WADA added the steroidal module. ‘We also collect urine for variations in testosterone,’ says Banuls, ‘but guidelines for the hormonal module are ongoing.’

The ABP analyses blood and urine, but it’s blood that’s assessed for the haematological module. Once the rider’s blood is taken, the main constituents that are analysed are reticulocytes and haemoglobin. ‘These are the most important ones we focus on in cycling,’ says Banuls. ‘Together they produce what’s called an OFF-score, which is the ratio of the two numbers.’

They’re important in cycling because you can deliver greater volumes of oxygen to working muscles if your blood is packed with higher levels of reticulocytes and haemoglobin. A physiology recap will explain why. Haemoglobin is the oxygen carrier in blood, extracting it from the lungs and sending it to the tissues. Reticulocytes are immature or new red blood cells, which carry haemoglobin. Reticulocytes only take about a day to mature, meaning a certain percentage of your red blood cells are reticulocytes at any one time.

Injecting yourself with EPO will stimulate your body to produce more blood cells, increasing the percentage of reticulocytes. The other primary method of doping – blood transfusion – requires removal of your blood before re-infusion. That initial drop screams at the body to compensate by making more red blood cells, again leading to a higher-than-normal percentage of reticulocytes. But this is where things become complicated and why the ABP is so effective. ‘While reticulocytes skew upwards after immediate doping, when you re-infuse your blood [with the blood you stored in the fridge], your actual percentage of reticulocytes drops because the “older” blood effectively dilutes the new blood,’ says Professor Chris Cooper, the biochemist author of Run, Swim, Throw, Cheat. Haemoglobin plummets when you first extract blood, but increases on re-infusion, which is why the ratio of the two can highlight potential doping.

Haematological scientists have observed that most people have reticulocyte percentages in their blood of between 0.5 and 1.5%. Some are naturally higher or lower but it’s the spikes or drops that the testers are eyeing. Though not 100% proof, it’s created a more stringent system. ‘In the past it was far too easy to mask abuse,’ says Cooper. ‘I’d say it’s much more difficult now.’

Masking the past

In the United States Anti-Doping Agency’s (USADA) analysis of Armstrong’s undetected doping regime, they surmised how the Texan avoided detection as follows: ‘The respondents [Armstrong, a team director, team captain and team doctors] implemented a number of means to avoid detection of EPO use, including: micro-dosing (ie using smaller amounts of EPO to reduce the clearance time of the drug), intravenous injections (ie injecting the drug directly into the vein rather than subcutaneously to reduce clearance time), saline, plasma or glycerol infusions (to reduce concentration)…’

The UCI would now argue that, with more tests in and out of competition, and with the ABP, riders have a significantly greater chance of being caught and so will choose to ride legally. That argument is supported by research undertaken by its scientific advisor Dr Mario Zorzoli. He analysed reticulocyte levels of professional riders between 2001 and 2010. He observed that in 2001, 14% of athletes showed abnormal levels. In 2010, two years after the introduction of the ABP, that figure had dropped to less than 3%.

It can’t be concluded that doping has stopped, but it’s a strong indicator that it has lessened thanks to the ABP. For riders to dope and yet evade being exposed by the ABP, they would have to dope continuously, which Cooper suggests would be extremely difficult logistically, and very damaging to long-term health. ‘If you’re a committed doper, you’d basically have to dope all the time. There would be no let up,’ he says. 

Yet as Lance showed, impracticality is little deterrence when success, power and a kiss on the podium is concerned. But it seems the riders and stakeholders are beginning to believe – and encourage – this new, clean world. Iwan Spekenbrink is the general manager of Giant-Alpecin. He’s the driving force behind the Dutch team’s ascent from racing at Pro Continental level as Skil Shimano to today’s world-class set-up that includes John Degenkolb.

‘We started the year before the Puerto scandal [2005] and, in my opinion, we couldn’t have done what we’ve done if we weren’t clean,’ says Spekenbrink, alluding to the scandal that implicated many riders including Alejandro Valverde, Alberto Contador and Ivan Basso of working with the doping doctor Eufemiano Fuentes. Only Valverde was punished based on Puerto evidence.

Spekenbrink explained to his young charges that doping wouldn’t be tolerated or needed. He convinced them they’d work with the best nutritionists, aerodynamicists, coaches and support staff to improve their performance. He also forged a democratic environment where everyone is responsible for maintaining a clean team.

‘It’s not all about the doctors keeping an eye on blood levels,’ he says. ‘It’s for the trainers to see how their power output is in training. If they see a strange skew, they should report it. You also need to look at the riders. If you pay attention, you can see by their behaviour if they’re cheating or not. That’s helped. Observing those indirect markers and looking for fluctuations is a step in the right direction.’

A question of resources

The road to redemption doesn’t always run smooth, though how times have changed. In the past, riders have resorted to going on strike when the authorities have dared clamp down on doping. Take the 1998 Tour when, off the back of the Festina scandal, a Marco Pantani-led peloton staged a sit-down protest at what they perceived as the organiser’s antagonistic handling of the situation. As it transpired, it’s suspected that up to 90% of riders racing that day were on some form of banned ergogenic. In 2014, thanks to the instant communication channels like Twitter, athletes are now criticising the UCI for holes in its testing programme.

‘UCI control last night,’ tweeted Tinkoff-Saxo’s Nicolas Roche in April. ‘ISC [Irish Sports Council] this morning done by same agency. Can’t u [sic] communicate so you can do more effective control and test more riders?’

More recently, Chris Froome used the same social platform to vent his disappointment at the anti-doping programme after Contador, Nibali and himself had each undertaken a training block in Tenerife ahead of the Criterium du Dauphiné. ‘Three major TdF contenders on Mount Teide and no out-of-competition test for the past two weeks,’ he tweeted, adding, ‘It’s in all our best interests to be able to prove we are clean no matter where we train.’ Froome later confirmed that he’d only been tested once in five training camps on the island. It begs the question: is there a resource issue?

‘Our ABP goal is to test riders out of competition at least three times,’ says Banuls. When you bear in mind there are 18 World Tour teams with a maximum of 30 pro riders and then consider the 4,352 out-of-competition ABP tests in 2012, the UCI is hitting its target, though concedes that extra resource would make the system tighter. 

‘It’s true that it becomes expensive when you’re blood testing a large pool of riders away from the race circuit,’ says Banuls. ‘Urine is cheaper but not significantly so.’

According to Cannondale Pro Cycling manager Jonathan Vaughters, each World Tour team donates ₣120,000 per annum to the UCI for the anti-doping programme. That’s ₣2,160,000 purely from World Tour teams (added to money from the Pro Continental teams, which must also adhere to the ABP). That sounds a lot but the total cost of creating passports in the first place was 4.2 million Swiss Francs in 2010 (₣3.1 million). [2014 statistics]

The UCI wouldn’t disclose costs for each biological test, but the price of a standard EPO out-of-competition test from the Australian Sports Anti-Doping Authority is £618. The full urine test is £460. 

In 2012, the CADF received £4,656,300 from the teams, UCI, riders and organisers. It spent £4,512,420 of that on the men’s road-racing anti-doping programme. In short, a clean sport doesn’t come cheap. 

Tests on a global scale

The accessibility of WADA-accredited laboratories is also an issue. There are 32 around the world with 18 in Europe, six in Asia, one in Oceania, five in North America, and just one each in South America and Africa, perhaps explaining why Froome’s urine and blood was never collected in neighbouring Tenerife. The closest lab is in Lisbon, which is a long plane journey away and presents logistical issues.  

‘It’s a challenge to keep the blood cool if the laboratory’s far away,’ says Banuls. There’s also concern that with each passing minute in transit, traces of doping dissipate. Spekenbrink recommends the introduction of more mobile laboratories, which would inevitably improve the system, albeit at a cost. 

The effect of altitude training is another grey area. Henao’s return to racing followed an investigation into anomalous doping results in his native Colombia. To their credit, Team Sky alerted the UCI to their results and flew Henao back to his homeland to take part in a high-altitude research programme. 

‘Sergio was raised in the mountains, goes back in winter, and lives and trains at different levels,’ Brailsford said at the time. ‘We’ve looked as far as we can at the effects of this. Our understanding is limited by a lack of scientific research into “altitude natives” such as Sergio. We’re commissioning independent scientific research to better understand the effects of prolonged periods at altitude after returning from sea level, specifically on altitude natives.’

April 2016: A Team Sky statement reads 'Sergio has this week been contacted by the CADF with a request for more information with regards to readings on his Athlete Blood Passport between August 2011 to June 2015.'

'We continue to support Sergio and remain confident in the independent scientific research which was undertaken. We will be helping Sergio make his case robustly over the coming period. He will also withdraw from racing until the issue is resolved given this contact from the CADF and the very obvious distraction to him.  There is no obligation on us to do this but it is team policy if and when a formal process such as this begins.'


Broadly speaking, the effects of altitude (anything over about 1,600m) on haematocrit levels (the percentage of red blood cells in blood) are well known. At altitude, air is less dense, meaning each breath delivers less oxygen to the body. When you take a breath at 3,500m, for instance, you’re breathing in 40% less oxygen than you would at sea level. Our bodies increase red blood cell production to capture more of the oxygen in the air.

‘It’s why the Andean people are known to have particularly high haematocrit levels,’ says Cooper. Historically, riders with a value above 50% would be suspended, but this was dropped on introduction of the ABP. ‘But there’s also a genetic component. There was the case of Eero Mäntyranta, a cross-country skier who won three Olympic golds in the 1960s. He had a genetic mutation that resulted in an incredibly high haematocrit. Lance Armstrong had naturally low levels, which explains why doping gave him such a boost.’

Every ABP sample is accompanied by an athlete questionnaire, with Banuls stressing that athletes are asked to reveal if they’ve been at altitude within the past two weeks. This is corroborated by ADAMS (Anti-Doping Administration and Management System), which requires athletes to specify where they’ll be for an hour a day, seven days a week, for up to three months in advance, for random drug tests. 

Leading the way

Cycling is no victim. The sport had a code of silence (omerta) and a desire to race higher, faster and stronger at all costs. Now cycling is leading the way, with its ABP tests making up a remarkable 35.8% of tests across all Olympic sports in 2012. This compares to cash-rich sports such as football and tennis conducting just 3% and 0.4% respectively. ‘Let’s be clear about this: it’s not in your DNA when you’re born that you’ll be a cyclist and dope,’ says Spekenbrink. ‘It’s a logical system that if there’s a lot of money at stake and it’s the best against the best, there’s a doping product that will benefit you. All sports should be on the ABP. Any that aren’t are in denial.’

Can we ever know a rider is clean? History suggests not. Cases like Chris Horner, who won the 2013 Vuelta at the age of 41, raise concern, especially after he published six years’ worth of biological data to fend off accusations of doping. It merely served to fan the flames, with experts claiming values in his profile, including reticulocyte and haemoglobin at the Vuelta, were abnormal. That debate continues, and no one would claim the system’s bulletproof – there’s a ‘false positive’ in every 1,000 results – but hopefully the days of masking EPO use simply by pumping your veins with saline are over.

Testing procedure - what actually happens?

  • The doping control officer or chaperone informs the rider or team that they’re to accompany them to the doping control building. Only under the following circumstances can the rider delay proceedings: victory ceremony; media commitments; further competitions; warm down; medical treatment; locating a representative/interpreter; obtaining photo ID. The athlete is kept under strict observation at all times.
  • A urine sample is provided in view of an official of the same gender, split into two bottles and sealed by the rider.
  • A code number is attached to the bottle and recorded on the relevant paperwork to ensure accuracy and anonymity.
  • The athlete completes a medical declaration stating all medicines and drugs consumed in the past week. If any of these substances are on the WADA prohibited list, the athlete must hold a Therapeutic Use Exemption (TUE).
  • Both parties sign the form and each is given a copy.
  • Both samples are sent to a WADA-accredited laboratory (if there’s not one on site). Sample ‘A’ is tested using gas chromatography – which separates the contents of the sample, and mass spectrometry – which provides the molecular specification of the compounds. If the result is positive, the athlete is notified before sample ‘B’ is tested.
  • The athlete or a representative is allowed to be present at the unsealing and testing of the second sample. If this is positive, too, the relevant sporting organisation is notified and will decide on subsequent punishment.

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