The World Anti-Doping Agency -WADA- has highlighted several recent successes achieved through the Athlete Biological Passport -ABP-, a tool that builds individual profiles by tracking selected markers in blood and urine over time. Its new applications have helped identify cases of steroid use, flag a sample that led to the first anti-doping rule violation associated with the Endocrine Module and uncover sample substitution. The system also continues to provide evidence in blood doping cases and guide targeted testing in endurance sports.
Unlike conventional testing, the passport does not necessarily need to detect a prohibited substance directly in a single sample. It compares each athlete’s results with their own previous values and establishes individual reference ranges. When a deviation appears, an anti-doping organisation can order further tests, conduct additional analyses, store the sample for future examination or open an investigation. An alert does not automatically constitute a violation, but it can generate the evidence required to establish the use of a prohibited substance or method. WADA President Witold Bańka believes these functions deliver “a significant return on investment for athletes worldwide”.
From blood and urine to hormones
WADA began implementing the passport in December 2009 through the Haematological Module, developed to identify changes consistent with the use of erythropoietin (EPO), blood transfusions or other forms of blood manipulation. In 2014, it introduced the Steroidal Module, which established longitudinal profiles using variables measured in urine to detect testosterone and other anabolic steroids. The tool therefore progressed from identifying indications mainly associated with oxygen transport to also examining how each athlete’s hormonal profile changes over time.
The next expansion arrived in 2023 with new blood-based steroid markers and the Endocrine Module, which targets growth hormone and related substances. Blood markers have proved particularly useful for individuals who excrete low levels of steroids in their urine. Athletics Integrity Unit -AIU- Head of Testing and Compliance Thomas Capdevielle said their impact was “immediate” because they provided complementary information when urine data alone was insufficient to establish doping. The Endocrine Module also identified a suspicious sample that underwent a specific growth hormone differential isoform analysis and ultimately led to the first violation associated with the new tool.
When a sample belongs to someone else
Long-term monitoring can also reveal that a sample may not have come from the person who was supposed to provide it. Differences between an athlete’s historical profile and a new analysis may indicate that their urine has been replaced with a clean sample. This process helped identify sample manipulation involving seven Russian athletes in 2007. Ten years later, the Athlete Passport Management Unit -APMU- at the Cologne laboratory detected numerous cases in weightlifting and helped initiate Operation Arrow, a covert investigation into urine substitution during the collection process.
The same application was demonstrated by Operation Obsidian, whose findings were published in March 2026. The investigation uncovered sample substitution in Georgian rugby and breaches by the country’s anti-doping agency. WADA Intelligence and Investigations Director Günter Younger said the analytical expertise and operational guidance provided by APMUs had been instrumental in identifying and substantiating those practices. Following the case, his department recommended that anti-doping organisations immediately contact their management unit whenever a sample is flagged as potentially suspicious. The network comprises units housed in 17 WADA-accredited laboratories, which manage passports independently and anonymously.
From biological data to an investigation
The Haematological Module continues to produce adverse analytical findings for substances such as EPO, as well as cases based on abnormal changes within the passport itself. The International Testing Agency -ITA-, which oversees anti-doping activities for the Union Cycliste Internationale -UCI-, has recently used these abnormalities in cases that resulted in sanctions against several cyclists. Its Head of Science and Medical, Neil Robinson, warns that collecting data is not enough: “The more curious and sceptical you are of the ABP data, the greater your chances of uncovering meaningful abnormalities.” Specialists must then translate that biological information into targeted testing, specific analyses or investigative leads.
One of the most extensive examples comes from Portugal. Since its anti-doping authority began working with the Rome APMU in 2019, it has pursued more than a dozen cases involving cyclists’ biological passports. In 2021, haematological abnormalities provided evidence of potential team-level doping within W52/FC Porto. The authority subsequently worked with the police on Operação Prova Limpa, described by WADA as the largest doping investigation in Portuguese sport. The passport did not replace police work or subsequent analyses, but it helped turn individual abnormalities into an investigation of possible collective practices.
New markers and artificial intelligence
The next stage aims to expand the markers available in the Haematological, Steroidal and Endocrine Modules, identify medical or environmental factors that could affect results and reduce analysis costs. WADA is also studying alternative sample types that can retain greater stability during transport and storage. Another area focuses on multidimensional methods, machine learning and artificial intelligence capable of finding relationships that are difficult to recognise by examining each variable separately. Bańka has identified securing further public funding to support this research as one of the agency’s priorities.
WADA Associate Director of the ABP Reid Aikin expects new functions to be introduced gradually to improve detection, guide intelligence-led testing and support investigations. Part of this development will be examined at the fourth Athlete Biological Passport Symposium, which WADA will hold from 27 to 29 September 2027 in Tokyo, Japan. The event will bring together experts, laboratories and anti-doping decision-makers to harmonise the interpretation of profiles and define the tool’s next applications. Since 2009, the passport has evolved from monitoring changes in blood to connecting biological data, specific analyses and international investigations.
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