Conventional Chromogenic Heparin Assays are Influenced by Patient's Endogenous Plasma Antithrombin Levels
Bibliographic record
Abstract
OBJECTIVES: To determine, in vitro, the influence of plasma AT concentrations on heparin levels as measured by commercially available chromogenic kits. METHODS: Purified AT was added to plasma that was immune depleted of AT at the following final concentrations: 0, 0.5, 1.0, 1.5, 2.0, 2.5 u/ml. Heparin was added to each of the AT concentrations at the following final concentrations: 0, 0.2, 0.4 u/ml. Heparin levels were then determined using 5 different Anti-Xa (n=4) or Anti-IIa (n=1) commercial kits. All kits provided purified AT to be added to the assay system. RESULTS: When heparin was added to plasma, heparin concentrations measured were dependent on plasma concentrations of AT (p<0.001). When plasma concentrations of AT were less than 1.0 u/ml heparin concentrations were underestimated and when plasma concentrations of AT were greater than 1.0 u/ml actual heparin levels were over estimated. There was no significant difference in the findings between the various commercial Xa or IIa kits. In the absence of heparin, anticoagulant activity was detected when plasma AT concentrations were above 1.0 u/ml. There was a statistically significant correlation between plasma concentrations of AT and the amount of anticoagulant activity (p<0.001). CONCLUSIONS: Conventional chromogenic heparin assays are influenced by endogenous plasma AT levels.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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; both teacher heads agree on what is shown here.
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".