Time to positivity as a diagnostic tool for catheter-related candidemia: a species-specific analysis

Abstract

Objectives: Early identification of the source of candidemia is critical for catheter management. Time to positivity (TTP) is an accessible marker of catheter-related bloodstream infection in bacteremia, but its role in candidemia remains unclear. We evaluated the ability of TTP to predict catheter-related can- didemia across major species and compared its performance with differential time to positivity (DTP). Methods: Single-center retrospective study assessing the diagnostic utility and optimal TTP cut-offs for catheter-related candidemia. Predictors of catheter-related source were analyzed using multivariable lo- gistic regression. Results: Among 544 episodes, 407 were analyzed. In C. albicans (n = 133) and C. parapsilosis (n = 100), TTP differed significantly by source. In C. albicans , TTP ≤27 h predicted catheter-related candidemia (sen- sitivity 71.8%, specificity 70.2%, Positive Predictive Value (PPV) 50.0%, Negative Predictive Value (NPV) 85.7%) and was the only independent predictor (OR 5.1 [2.1-12.1], P < 0.001). In C. parapsilosis , TTP ≤35 h showed sensitivity 77.5%, specificity 51.7%, PPV 51.7%, NPV 77.5%, and remained independently associated (OR 3.1 [1.2-8.0], P = 0.017). Although DTP ≥2 h was more frequent in catheter-related candidemia by C. parapsilosis , the TTP ≤35 h was the strongest predictor. Conclusion: TTP outperformed DTP in identifying catheter-related sources in C. albicans and C. parapsilosis candidemia and may support timely catheter management.