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A Closer Look: The Athlete Biological Passport

“Anti-doping is moving rapidly toward a more forensic approach to protect clean sport through analytical and non-analytical investigations. The Athlete Biological Passport is a scientific tool to examine relevant indirect biomarkers of doping which further allows those that aim to level the playing field with the ability to detect and deter doping through state-of-the art and complementary methods – as an analogy, we are working to create a video of an athlete’s biochemistry rather than merely looking at a snapshot in time.” – USADA Science Director Matthew Fedoruk Ph.D

Here at USADA, we receive regular inquiries regarding the role the Athlete Biological Passport (ABP) plays in our anti-doping efforts. The ABP is an important tool for anti-doping organizations in the fight against drugs in sport, specifically in that it allows for the long term monitoring of an athlete’s biological data in both blood and urine as well as the monitoring of potential markers that indicate doping. Given the increased discussion regarding the ABP in recent weeks, we wanted to take a moment to share some information about what it is and how it is used. It is important to note that while the ABP is not a cure all test, it is an important part of our overall anti-doping program.

Here are answers to four of the most commonly asked questions regarding the Athlete Biological Passport:

  • What is the ABP?

The principle behind the Athlete Biological Passport (ABP) is the monitoring of selected biological parameters over time that may indirectly reveal effects of doping on the body. This approach allows anti-doping organizations to generate individual, longitudinal profiles for each athlete and to look for any fluctuations that may indicate the use of performance-enhancing drugs or methods. The longitudinal profile for each athlete is generated based on statistical tools that utilize data from an athlete’s previous samples to predict the likely individual limits or reference range for future samples. If any data from a sample falls outside of the athlete’s reference range, this abnormal value may be an indication of doping or a pathological condition. This data can also be used to conduct targeted, conventional anti-doping tests on athletes with abnormal profiles. ABP data can also be used as corroborating evidence of doping during an anti-doping rule violation case.

  • What are the variables that are monitored in the Athlete Biological Passport?

Initially, only the hematological biomarkers had been validated by WADA for the ABP. Hematological biomarkers that are measured and can be used for blood profiling include hemoglobin, hematocrit, red blood cell count, reticulocyte number, reticulocyte percentage, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration and OFF-score. In 2013, the WADA Athlete Biological Passport Guidelines introduced a second module, the Steroidal Module, which became operational on January 1, 2014. The Steroidal Module tests an athlete’s urine sample to observe unique steroidal variables, therefore making it a useful technique in spotting athlete abuse of Anabolic Androgenic Steroids. The urinary steroid profile consists of the urinary concentrations of Testosterone, Epitestosterone, Androsterone, Etiocholanolone, 5a-androstane-3a,17β-diol and 5β-androstane-3a,17β-diol, together with the specific gravity of the urine sample. The model used by the ABP replaces the ‘population reference’ approach with an ‘intra-individual’ approach, which allows for a more refined evaluation.

  • Can the ABP replace traditional anti-doping testing?

Drug testing in sports relies on various strategies that include the direct testing of athletes for the presence of performance enhancing agents as well as the evidence gathered through the non-analytical or indirect approach. While the approach of detection of prohibited substances or their metabolites in an athlete’s blood or urine sample is an effective approach, it has its limitations. With the onset of new or modified substances or designer drugs being misused by athletes, anti-doping agencies seek new detection strategies to combat these emerging threats. Thus, the Athlete Biological Passport provides a complementary and more sophisticated strategy to traditional analytical testing in an effort to scientifically gather evidence of possible doping in sport. The ABP is one tool in a kit of intelligent anti-doping practices meant to deter and detect the use of prohibited substances in sport.

  • Will the volume of blood collected for testing affect my performance?

On average, the total volume of blood collected for testing is relatively small, less than two tablespoons (~15mL). This compares to the total volume of blood in a human of between roughly 200-400 tablespoons (3000-6000mL), depending on the individual’s size and sex. Trained and experienced phlebotomists are trained to make the sample collection process as quick and painless as possible. The withdrawal of such a small amount of blood will not have any effect on athletic performance.

The Athlete Biological Passport Guidelines is a document that has been approved by WADA’s Executive Committee and it outlines a framework that ensures the consistency of application and implementation of the ABP. This document provides an overview of the scientific principles behind the blood module as well as mandatory requirements for collection, transportation, analysis and results management of the blood samples.  National anti-doping organizations use the ABP to complement their toolkit in an effort to detect and deter doping in sport.


Further Reading:

WADA Athlete Biological Passport webpage

WADA Athlete Biological Passport and the Steroidal Module

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