Biological passport analytics are used in anti-doping testing to monitor athletes for signs of doping by analyzing biological markers over time. Which choice best captures this idea?

• A. Testing only during events
• B. Random sampling without records
• C. Only the chemical composition of urine
• D. Monitoring biological markers over time

Answer: (D)

Biological passport analytics focus on monitoring biological markers over time. By repeatedly measuring a set of biomarkers in an athlete and tracking how their levels change across different times, competitions, and training cycles, investigators can see patterns that rise above normal individual variation. Each athlete serves as their own reference, so they can detect sustained shifts or coordinated changes across markers that suggest doping, even if a single test looks normal. This time-based, within-person approach is the core strength, because it reveals anomalous trends rather than relying on isolated values. Other ideas that rely only on one-off tests, random sampling without history, or just the chemical makeup of urine miss this dynamic, longitudinal perspective and are less capable of identifying doping signals.