Using Peptide Markers in Dried Blood Spots to Verify When Athletes Collected Their Anti-Doping Samples

Ten volunteers provided dried blood spot samples that were stored for up to 91 days at three temperatures (room temperature, 4°C, and -20°C). Samples were collected at 12 time points. Using a targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, researchers measured changes in specific peptide sequences over time. They created ratios of two peptides from the same parent protein and tracked how these ratios changed with storage duration and temperature. Method validation included intraday precision, carryover testing, and sample extract stability.

The World Anti-Doping Agency recently approved dried blood spots for routine doping control. This opens the door to athletes collecting their own samples remotely — but that creates a trust problem: how do you verify when the sample was actually taken? This study addresses that gap by identifying peptide markers that change predictably over time, essentially creating a biological timestamp. If validated further, this could make remote anti-doping monitoring more reliable and harder to cheat.

Dried blood spots are transforming how anti-doping testing is done — moving from supervised in-person collection to remote self-sampling. But this shift requires new ways to verify sample integrity. Peptide-based time markers are an elegant solution because they rely on natural biochemical degradation that would be very difficult to fake. This research is part of a broader trend using peptide analysis not as the target of detection, but as a forensic verification tool.

Small sample size of only 10 volunteers, which may not capture the full range of biological variability. The significant peptide ratio changes were only observed at room temperature storage after 28 days — the method may not work for samples stored at cooler temperatures or for shorter time periods. This is a proof-of-concept study; large-scale validation in real doping control scenarios hasn't been done yet.