Urine-Blood Culture Concordance in Suspected Urosepsis and Implications for Early Clinical Decision-Making

To assess microbiological concordance, antimicrobial susceptibility testing (AST) agreement, and associated clinical characteristics of suspected urosepsis episodes using paired urine (UC) and blood cultures (BC).

We retrospectively analyzed 2,572 paired UC-BC episodes from 2,302 adults at a tertiary-care laboratory (2018-2024). Episodes were considered concordant when UC and BC shared at least one identical pathogen. We compared pathogen spectra, culture dynamics, AST results, laboratory referral information, inflammatory markers, and survival. Multivariable logistic regression was used to identify factors associated with concordance.

Of 2,572 episodes, 1,405 (54.6%) were concordant. UC reports were finalized earlier than BC reports, with 50.4% available within one day. Concordant episodes showed shorter BC time-to-positivity than discordant episodes (7.8h vs 14.1h). Documented clinical suspicion and detection of Escherichia coli or Staphylococcus aureus in UC were associated with concordance. Among concordant Enterobacterales episodes, UC AST showed high agreement with BC AST. In exploratory analyses, concordant episodes were associated with faster decline of inflammatory markers and better survival.

In suspected urosepsis, UC frequently identified the same pathogen as BC while providing earlier microbiological and susceptibility information. These findings support the potential early diagnostic and antimicrobial stewardship value of UC while BC results remain pending.