Assessing EPO stability in urine and comparing recombinant EPO detectability in matched urine, venous serum, and capillary serum following a controlled epoetin alfa administration
Bibliographic record
Abstract
The instability of erythropoietin receptor agonists (ERAs, i.e., EPO) in urine presents a challenge to their detectability in doping control samples; however, this issue is not often seen in blood (serum) samples. With the anti-doping field beginning to transition into alternative blood collection technologies, it is important to understand recombinant EPO (rEPO) detectability in serum samples collected from one such capillary collection device, the Tasso+ SST. Twelve individuals were administered a single, 40 IU/kg dose of rEPO (epoetin alfa, EPOGEN®). Following administration, matched urine, venous serum, and capillary serum samples were concurrently collected. Urine aliquots were subject to various storage times and temperatures mimicking shipping conditions of doping control urine samples to assess EPO stability, while other urine aliquots, venous serum, and capillary serum aliquots were frozen until analysis to understand rEPO detectability across all three matrices. EPO and rEPO instability was identified in urine collected from 8 of 12 participants, especially in aliquots stored at room temperature and 37°C. In some of these unstable samples, rEPO was still detectable, while in others, no recombinant nor endogenous EPO was detectable and would have resulted in negative sample reports. Analyzing the concurrently collected urine, venous, and capillary serum samples, rEPO detectability was identical across the three matrices. In most cases, rEPO was detectable for at least 168 h post-administration. Noting greater stability in blood compared with urine, it is recommended that anti-doping authorities utilize this novel capillary serum collection technology to improve overall ERA detectability in doping control samples.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".