Comparison of clot-based and chromogenic assay for the determination of protein c activity
Bibliographic record
Abstract
: Activated protein C inactivates factor Va and VIIIa. Deficiency of this natural anticoagulant may result in recurrent venous thrombosis. Performance characteristics of clot-based and chromogenic protein C activity assays are different. The clot-based assay has limitations because of interference with coagulation inhibitors resulting in spuriously increased protein C levels or underestimation because of elevated levels of factor VIII and Factor V-Leiden mutation. The chromogenic assay is not influenced by such interferences but only detects functional defects of protein C that involve the active site rendering it insensitive to rare mutations. To compare two methods, we conducted a retrospective study from January 2015 to June 2017. Our results showed a good correlation between clot-based and chromogenic assay (R = 0.94 and r = 0.88). The study of agreement between the two methods by the Bland-Altman method showed that chromogenic method on an average measures 7.8% more protein C than that of clot-based. The results also showed that the bias between the two methods is significant. The positive trend noted was contributed by the values of less than 20% of protein C. Both clot-based and chromogenic assays had high sensitivity; however, the chromogenic assay showed better specificity (97%) as compared with the clot-based assay (93%). In conclusion, we recommend the chromogenic method as the assay of choice, which is also recommended by the College of American Pathologist Consensus Study over activated partial thromboplastin time-based assay. We have shown here that despite a good correlation between the two techniques, there is a difference as highlighted by the difference plots.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.013 | 0.027 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.006 | 0.005 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".