Clinical Associations and Significance of Biphasic aPTT Transmittance Waveforms.
Bibliographic record
Abstract
Many modern automated coagulometers determine coagulation parameters such as the PT and aPTT using optical endpoints. One instrument (MDA-180, BioMerieux, Durham, NC) continuously monitors changes in optical transmittance through the specimen over the course of clot formation, and is able to analyze measurements derived from the resulting waveform. The waveform is typically sigmoid, with a sharp drop in transmittance at the time of clot formation. In some specimens, a biphasic waveform (BPW) pattern has been observed, in which the normally flat pre-coagulation segment has a negative slope prior to the sharp drop in transmittance associated with clot formation. The BPW pattern has been associated with sepsis, DIC, and increased mortality in adult patients. The Special Haemostasis Laboratory of the Health Sciences Centre in Winnipeg, Canada uses the MDA-180 for all automated coagulation assays. Over a two-year period (August, 2002 to July, 2004), a BPW was identified in 21 adult and 12 pediatric patients. Hospital records of these patients were reviewed for details of their clinical condition, and coagulation test results were examined for presence of hemostatic abnormalities. Sepsis was a common diagnosis at the time of detection of the BPW, seen in 57% of the adults and 42% of the children. However, 4 adults (19%) and 4 children (33%) were identified during routine investigations for clinical bleeding or thrombophilia. In contrast to previously reported studies, DIC was less prevalent, seen in only 7 (33%) of the adults and 3 (25%) of the children. The presence of lupus anticoagulants, alone or in conjunction with other coagulation abnormalities, was observed in 8 adults (38%) and 9 children (75%). This association has not previously been reported. Nine adults (43%) and four children (33%) died, all from complications of sepsis. Despite the small sample size, this study questions the clinical utility and specificity of the BPW as an indicator of sepsis and DIC. The association with DIC seems particularly weak in the pediatric population, in which the BPW has not been previously evaluated. Further study is required to determine the strength of the association between the BPW and DIC, and to identify other clinical and laboratory conditions, such as lupus anticoagulants, which may confound this association.
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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 | 0.001 | 0.008 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 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 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".