Differential time to positivity: Vascular catheter drawn cultures for the determination of catheter-related bloodstream infection
Bibliographic record
Abstract
BACKGROUND: Vascular access catheter-related infections are common. The purpose of this study was to evaluate the accuracy of differential time to positivity (DTP) comparing 2 blood cultures drawn through different lumens of a multi-lumen central venous catheter (CVC DTP) for the diagnosis of catheter-related bloodstream infection (CRBSI). METHODS: This study was performed at a single institution (Health Sciences Centre, Winnipeg, Manitoba, Canada). Microbiology laboratory blood culture records for the period January to November 2009 were retrospectively reviewed. All adult patients with a positive peripheral blood culture and a minimum of 2 positive central line cultures (same organism) drawn from separate lumens of a multi-lumen CVC, all obtained at the same time on the same day, were included in the study. DTP supporting CRBSI diagnosis was defined as a difference in time to positivity of ≥ 2 h between a peripheral blood culture and a CVC blood culture (peripheral DTP), or between 2 CVC blood cultures from different lumens of a multi-lumen catheter (CVC DTP). Peripheral DTP was used as the reference standard for CRBSI diagnosis. RESULTS: Thirty-five episodes of bacteremia from 33 patients were included in this study. CVC DTP had a sensitivity of 76.5% and a specificity of 88.9% for CRBSI diagnosis, using peripheral DTP as the reference standard. CONCLUSIONS: These data suggest that CVC DTP may be of benefit in the diagnosis of CRBSI. Further study is required to better define the patient population/catheter type for which CVC DTP would be of greatest benefit.
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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 | 0.002 | 0.017 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".