Total Prostate-Specific Antigen Testing in Capillary Samples: Back to the Future
Bibliographic record
Abstract
To the Editor: In the March 2025 issue of The Journal of Applied Laboratory Medicine, Sodi et al. examine the relationship between capillary blood (CB) total prostate-specific antigen (PSA) and venous blood PSA and conclude that the 2 measurements are practically equivalent (1). CB total PSA, due to its collection simplicity and stability, was then suggested to be an alternative when PSA is used to investigate prostate cancer and other prostatic diseases. The authors also suggest that further validation work is now required for the measurement of total PSA in CB and determining outcomes in men with prostatic diseases. Approximately 20 to 30 years ago, we and others examined the feasibility of using CB, obtained by ear lobe stick (2) or finger prick (3, 4), to assess total PSA in men who are suspicious for prostatic diseases. In these three earlier papers, the capillary whole blood was spotted on filter paper and shown to be very stable, even when the dry filter papers were subjected to increased temperatures during mailing (3). There was an apparent oversight wherein the current work evidently did not consider CB collected as whole blood spotted on filter paper (2–4) as equivalent to the fresh CB matrix. Unfortunately, as a result of this, the previous work using filter paper for collection was not cited or discussed. This similarity of the matrices is important so that readers are aware that PSA is stable both as capillary samples collected and analyzed as dried blood spots. This appears to be a “Back to the Future” moment where dried blood spot samples and the fresh CB sample type are likely both suitable for use in determining outcomes in men with prostatic diseases or perhaps even the more controversial intended use of prostate cancer screening. As such, both the earlier filter paper work and that of Sodi et al. may be useful as valid sampling techniques when samples are transported to the lab in a timely fashion, thus improving patient access to testing and saving valuable time for patients, especially those living in remote areas.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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".