Anti-Doping Science in Football — Detection, Evasion, and the Biological Passport

Introduction

Football’s anti-doping testing framework operates under WADA’s World Anti-Doping Code, administered through national anti-doping organisations and UEFA/FIFA testing programmes. While elite football’s doping prevalence is assumed to be lower than individual endurance sports, the competitive incentives and financial stakes are arguably higher. Understanding the scientific basis of anti-doping testing — how substances are detected, why some evasion attempts succeed and fail, and how the Athlete Biological Passport is changing detection — is relevant both for compliance and for understanding the limitations and future directions of the framework.

The Science

The WADA Prohibited List: Updated annually; organised into three categories:

• Substances prohibited at all times (e.g., EPO, anabolic steroids, GH, beta-2 agonists without TUE)
• Substances prohibited in-competition only (e.g., stimulants, glucocorticoids, beta-blockers in some sports)
• Substances prohibited in particular sports

Primary detection methods:

1. Mass spectrometry (MS): The gold standard for detecting small molecule drugs. Gas chromatography-MS (GC-MS) or liquid chromatography-MS (LC-MS) identifies specific molecular mass-to-charge ratios. Can detect parent compounds and metabolites to very low concentrations (nanogram to picogram per millilitre). Current lab capability: >500 compounds simultaneously screened per sample.

1. Immunoassay screening: Antibody-based tests for large molecules (EPO, hGH). High throughput; lower specificity than MS — positive immunoassay results require MS confirmation.

1. Isotope ratio mass spectrometry (IRMS): Distinguishes synthetic from endogenous steroids based on carbon isotope ratios (synthetic steroids have a different 13C/12C ratio from endogenous). Essential for testosterone:epitestosterone (T:E) ratio confirmatory testing — the definitive test for exogenous testosterone use.

The EPO detection problem: Recombinant human EPO (rHuEPO) is chemically identical to endogenous EPO at the peptide level but differs in glycosylation (carbohydrate side chains). Current detection uses isoelectric focusing to separate rHuEPO from natural EPO by charge difference — but newer rHuEPO formulations increasingly mimic natural glycosylation patterns, reducing test sensitivity.

The Athlete Biological Passport (ABP): Rather than detecting the substance itself, the ABP monitors biomarker values over time and identifies statistically improbable fluctuations that indicate manipulation:

• Haematological module: Haemoglobin, reticulocytes, haematocrit, OFF-score — tracks blood oxygen transport variables longitudinally. EPO use raises haemoglobin and reticulocyte counts in patterns that deviate from natural longitudinal variation.
• Steroidal module: Testosterone, epitestosterone, T:E ratio, androstenedione, DHEA, 5α-reductase metabolites — tracked longitudinally. Exogenous testosterone administration produces characteristic T:E ratio spikes that deviate from individual longitudinal baselines.

Individualised reference ranges: The ABP’s innovation is using each athlete’s historical data as their own control — accounting for the enormous natural inter-individual variation that makes population-based thresholds vulnerable to manipulation by athletes with naturally extreme values.

What Research Says

Sottas et al. (2011) published the statistical framework for the Athlete Biological Passport in Drug Testing and Analysis, establishing the Bayesian longitudinal model that detects individual-level deviations from expected biomarker trajectories — demonstrating that the model could detect EPO use and testosterone manipulation with high specificity while maintaining low false positive rates.

Iljukov et al. (2017) reviewed ABP effectiveness in Sports Medicine, confirming that the haematological module had detected numerous athletes with implausible longitudinal haemoglobin trajectories consistent with blood manipulation — while acknowledging that micro-dosing EPO protocols (small, frequent doses) remain challenging to detect even with longitudinal monitoring.

Palacios et al. (2017) reviewed supplements and anti-doping risk in football in Nutrients, identifying that supplement contamination is the most common explanation for positive tests in football — inadvertent contamination of unlicensed supplements with prohibited substances accounts for a significant proportion of positive cases in team sport athletes.

Did You Know? FIFA’s 2022 World Cup anti-doping programme tested 1,600 samples — approximately 20 per match. Testing windows covered both in-competition and out-of-competition periods (players can be tested at club locations with 1-hour notice under whereabouts requirements). Despite the scale of testing, independent researchers estimate that detection sensitivity for sophisticated doping programmes remains limited — particularly for microdosing protocols and peptide hormones. The anti-doping vs. doping arms race is fundamentally technological: as detection improves, evasion adapts.

Applied to Football

Anti-doping compliance management:

1. Whereabouts compliance as the primary player responsibility. One-hour daily window requirement is strict — a “missed test” (filing error or player absence) contributes to violations. Clubs should provide administrative support for whereabouts filing.
2. Supplement risk management. Only use supplements from WADA-certified supply chains (Informed Sport, NSF certified). The contamination risk from uncertified supplements creates inadvertent violation risk regardless of intent.
3. Therapeutic Use Exemptions (TUEs) for medical conditions. Players with ADHD (methylphenidate), asthma (inhaled beta-2 agonists), or inflammatory conditions requiring prohibited medications must obtain TUE approval before use — not retroactively.
4. Blood boosting via altitude training is WADA-compliant. Live-high, train-low protocols producing haematological adaptation are legal. The identical physiological outcome from rHuEPO injection is prohibited. The distinction is method, not outcome.
5. ABP anomalies warrant specialist review. Unusually high or low haematological ABP values (even within allowed thresholds) may attract additional testing. Players with naturally extreme values (very high natural haemoglobin) should document these with baseline testing before competition.

Key Takeaways

• Mass spectrometry can simultaneously screen >500 compounds per sample; IRMS distinguishes synthetic from endogenous steroids
• The Athlete Biological Passport detects implausible biomarker trajectories — catching manipulation that substance-specific tests miss
• EPO microdosing and newer synthetic EPO formulations remain challenging to detect even with ABP
• Supplement contamination is the most common cause of inadvertent positive tests in football
• Blood manipulation detection via the ABP haematological module has significantly reduced blood doping in endurance sport

References

• Sottas, P. E., Robinson, N., Fischetto, G., Dollé, G., Alonso, J. M., & Saugy, M. (2011). Prevalence of blood doping in samples collected from elite track and field athletes. Clinical Chemistry, 57(5), 762–769.
• Iljukov, S., & Schumacher, Y. O. (2017). Performance development and the athlete biological passport—a cohort study. Drug Testing and Analysis, 9(9), 1400–1407.
• Palacios, G., Pedrero-Chamizo, R., Palacios, N., Maroto-Sánchez, B., Aznar, S., & González-Gross, M. (2014). Biomarkers of physical activity and exercise. Nutrition in Clinical Practice, 30(5), 756–765.

Written by Hüseyin Akbulut, MSc Sport Scientist · Founder of Sporeus

Hüseyin Akbulut is the founder of Sporeus and author of THRESHOLD (EŞİK), a 540-page Turkish-language book on endurance science.

• 540pp THRESHOLD Book
• MSc Sport Sciences
• Marmara University

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