Combining PCT with CRP is better than separate testing for patients with bacteriuria in the intensive care unit: a retrospective study

Previous studies on PCT for urinary tract infections (UTI) have focused primarily on minors. This study investigated the predictive value of the neutrophil-to-lymphocyte ratio (NLR), C-reactive protein (CRP) level and procalcitonin (PCT) level in adult patients with bacteriuria in IUC.

This case‒control study included 85 patients with bacteriuria (PB) in the ICU from March 2021 to Jan 2024 based on positive urine culture results and a control group (n = 136) from Jan 2024 to March 2024. Patient data were collected using a hospital information management system. ROC curves of the NLR, CRP and PCT were use to predict the PB.

The AUCs of the NLR, CRP and PCT for the prediction of PB in ICU were 0.711 (95% CI 0.644–0.772), 0.855 (95% CI 0.800–0.900), and 0.884 (95% CI 0.832–0.924), respectively; the optimal thresholds were 8.02, 18.52 mg/L, and 0.215 ng/mL, respectively; the sensitivities were 69.0 (95% CI 56.9–79.5), 90.1 (95% CI 80.7–95.9), and 83.1 (95% CI 72.3–91.0), respectively; and the specificities were 67.6 (95% CI 59.1–75.4), 68.4 (95% CI 59.9–76.1), and 80.9 (95% CI 73.3–87.1), respectively. The negative predictive value (NPV) of CRP is greater than that of PCT. In bacteriuria caused by Candida infections, CRP and PCT have higher sensitivity and NPV.

Combined CRP and PCT testing is more helpful for diagnosing bacteriuria. CRP and PCT have higher sensitivity and NPV in diagnosing bacteriuria caused by Candida infection.