Utility of Differential Time to Positivity in Diagnosing Central Line–Associated Bloodstream Infections: A Systematic Review and Meta-Analysis

Abstract

Background Differential time to positivity (DTP), typically defined as pathogen growth at least two hours earlier from catheter vs paired peripheral blood cultures, is sometimes used to diagnose central line associated bloodstream infections (CLABSIs). Previous studies assessing DTP, however, have been small, provided conflicting results, and have not assessed heterogeneity across important subgroups. Methods We conducted a systematic review of the diagnostic characteristics of DTP for CLABSI, using MEDLINE, Embase, Web of Science, CINAHL, LILACS, AMED and the Cochrane database. Studies were eligible for inclusion if they reported sensitivities, specificities, predictive values, likelihood ratios, or 2x2 tables of DTP for diagnosing CLABSI. Extracted data were analyzed by creating forest plots, performing bivariate model meta-analysis, and assessing quality using QUADAS-2. Results Our search identified 274 records of which 23 met criteria for meta-analysis. Among 2,526 suspected CLABSIs, DTP demonstrated a summary sensitivity of 81.3% (95% CI 72.8-87.7%), specificity of 91.8% (95% CI 84.5-95.8%), positive likelihood ratio of 9.89 (95% CI 5.14-19.00), and negative likelihood ratio of 0.20 (95% CI 0.14-0.30). Covariate analysis based on catheter duration, study design, and patient immune status demonstrated no significant differences. However, DTP performed worse for Staphylococcus aureus (low sensitivity but high specificity) and Candida (high sensitivity but low specificity) compared to other organisms. Conclusion DTP performs well in ruling CLABSIs in or out. Obtaining paired catheter and peripheral blood cultures for DTP when the infectious source is unclear may prevent unnecessary line removal and diagnostic tests, although this needs to be balanced against potentially higher contamination rates from catheter cultures.

Understanding the diagnosis of catheter-related bloodstream infection: real-time monitoring of biofilm growth dynamics using time-lapse optical microscopy

“…worse results in terms of sensitivity and specificity to confirm Candida spp. and S. aureus C-RBSI, respectively ( Dhaliwal and Daneman, 2023 ). Other previous studies also revealed low ability of DTTP to discriminate between non-C-RSBI and C-RBSI caused by S. aureus ( Bouzidi et al., 2018 ; Orihuela-Martín et al., 2020 ).…”

Should Blood Cultures Be Drawn Through an Indwelling Catheter?

“…Additionally, in patients with long-term catheters, this finding may be a signal that the catheter is colonized and clinicians may consider catheter lock therapy in an effort to eradicate colonization of the catheter because studies have demonstrated that without intervention, such patients may go on to have microbial growth from percutaneously drawn cultures over the ensuing weeks [ 10 ]. When there is growth from both catheter-drawn and percutaneously drawn blood cultures, a differential time to blood culture positivity may assist in identifying the catheter as the source of the bloodstream infection [ 11 ]. On the other hand, the negative consequences of blood culture contamination should not be dismissed as blood culture contamination is clearly associated with extended length of hospital stay, inappropriate antibiotic use, and diagnostic confusion [ 12 ].…”