The Clinical Significance of Interleukin-6, C-reactive Protein, and Procalcitonin in the Early Recognition of Nosocomial Infections in Preterm Infants

Background: This study assessed the clinical value of interleukin-6 (IL-6), C-reactive protein (CRP), and procalcitonin (PCT) for early recognition of nosocomial infections in preterm infants.Methods: 120 neonates were enrolled, 89 with sepsis were compared with 31 noninfected controls. IL-6, CRP and PCT were measured at certain stages of infection. Receiver-operating characteristic (ROC) curve analysis was used to determine the best cutoff values of IL-6, CRP, and PCT for diagnosing sepsis.Results: The levels of IL-6, CRP, and PCT in the sepsis group were significantly higher than those in the control group before antibiotic treatment. In the sepsis group, IL-6 peaked 6 hours after the infection onset and dropped to normal 24–48 hours after the infection was controlled. The best cutoff values of IL-6, CRP, and PCT were >99.6 pg/mL, >9.27 mg/L, and >2.33 ng/mL, respectively. The areas under the ROC curves were 0.888, 0.823, and 0.953, respectively.When PCT was combined with IL-6 or IL-6 and CRP, the sensitivity and specificity were >85%.Conclusion: IL-6, CRP, and PCT are reliable indicators for early diagnosis of nosocomial infections in preterm infants. Combining PCT and IL-6 CRP, IL-6, and PCT levels could improve the accuracy of clinical diagnosis.