P-2088. Correlation of pediatric blood culture transport time and time-to-positivity since microbiology service centralization
Bibliographic record
Abstract
Abstract Background Guidance from Clinical & Laboratory Standards Institute (CLSI) and Infectious Diseases Society of America (IDSA) both recommend that transport of blood culture specimens from collection to laboratory accession should take less than 2 hours to preserve the specimen quality, such as positivity rate and time-to-positivity (TTP). This recommendation could be impractical in Canada as many diagnostic microbiology laboratories are moving towards centralization, in which microbiology services are relocated from individual laboratories to regional sites, where resources and personnel are consolidated. This is especially crucial for the pediatric population as different published guidelines are available on the required pediatric blood culture volume, which could affect their positivity rate and TTP. Methods The current study investigated the blood culture transport time and TTP for Children’s Hospital of Eastern Ontario (CHEO), a tertiary pediatric hospital, situated about 700 meters away from Eastern Ontario Regional Laboratory Association (EORLA) microbiology laboratory, which has consolidated the microbiology services for 18 hospitals in Eastern Ontario since 2010’s. All first positive blood cultures from patients at CHEO from 1 November 2019 to 31 October 2020 were included. TTP was defined as the time from collection to a positive signal from the automated incubators. Two-tailed Spearman’s correlation was used to determine the association between transport time and TTP. Results A mean transport time of 2.95 hours and a mean TTP of 31.8 hours were calculated from the 268 episodes of first positive blood culture from patients in a year (mean patient age 6.27 years). Only 82 specimens were transported to the laboratory in less than 2 hours. A weak but statistically significant correlation (rs = 0.17, p = 0.0047.) was observed between transport time and TTP. Conclusion Even for a hospital within walking distance of a regional microbiology laboratory, the blood culture transport time was unable to meet the guidance recommendation, associated with delay in TTP. Centralization of microbiology services could affect the quality of critical clinical specimens. Remedial actions, such as molecular testing, could be considered to salvage specimens if they are crucial for diagnoses. Disclosures All Authors: No reported disclosures
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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 | 0.007 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.013 | 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".