Usefulness of procalcitonin and C-reactive protein for predicting bacteremia in urinary tract infections in the emergency department

Abstract

Introduction: The aim of this study was to analyze and compare the capacity of procalcitonin (PCT), C-reactive protein (CRP), lactate and leukocytes to predict the presence of bacteremia in patients with urinary tract infections (UTIs).

Methods: Observational, retro-prospective analytical study of adult patients (≥15 years) diagnosed with UTI in an emergency department from August 2012 to January 2013.

Results: The study included 328 patients diagnosed with UTI, with a mean age of 52±22 years, 74% of whom were women. Of these, 43 (13.1%) had bacteremia. For predicting bacteremia, PCT achieved the largest area under the receiver operating characteristic curve (ROC-AUC) at .993 (95% CI .987-1; P<.001). A cutoff≥1.16ng/mL achieves a sensitivity of 100%, a specificity of 97%, a positive predictive value of 84% and a negative predictive value of 100%. Lactate achieved an ROC-AUC of .844, and CRP achieved only .534. The mean values when comparing PCT levels in patients with UTIs with and without bacteremia were 8.08±16.37 and .34±.37ng/mL, respectively (P<.001).

Conclusions: For patients with UTIs in the emergency department, PCT achieves considerable diagnostic performance for suspecting bacteremia, a performance greater than that of lactate, CRP and leukocytes.

Keywords: Bacteremia; Bacteriemia; Biomarcadores; Biomarkers; C-reactive protein; Emergency department; Infección del tracto urinario; Procalcitonin; Procalcitonina; Proteína C reactiva; Servicio de urgencias; Urinary tract infection.