Procalcitonin as a Biomarker for Bacterial Infections in Patients With Liver Cirrhosis in the Emergency Department

Objectives: The objective was to determine the diagnostic accuracy of procalcitonin measurement for bacterial infections in patients with all causes of liver cirrhosis. Methods: The authors conducted a cross-sectional study of 98 patients with cirrhosis treated in the emergency department (ED) of Chang-Gung Memorial Hospital, Taiwan. Serum procalcitonin levels and other clinical information were obtained concurrently. Patients were assigned to a sepsis or nonsepsis group after the medical records were reviewed by two emergency physicians blinded to the study. Receiver operating characteristic (ROC) curve analysis was conducted to determine the sensitivity, specificity, likelihood ratio, and suggested cutoff values. The diagnostic accuracy of the C-reactive protein (CRP) level was also determined for comparison. Results: A total of 98 patients were enrolled for analysis in 1 year. Twenty-seven patients (27.6%) were assigned to the sepsis group. Eleven patients (11.2%) had positive blood cultures. The areas under the ROC curves for procalcitonin and CRP in predicting sepsis were 0.89 (95% confidence interval [CI] = 0.77 to 0.92) and 0.81 (95% CI = 0.72 to 0.89), respectively (p = 0.11). The cutoff that maximized Youden's index was 0.49 ng/mL for procalcitonin and 24.7 mg/L for CRP. At these cutoffs, the sensitivity and specificity were 81.5 and 87.3% for procalcitonin and 80.0 and 80.3% for CRP. These results suggest that procalcitonin measurement shows at least an equivalent diagnostic accuracy to CRP measurement. Conclusions: Procalcitonin provided satisfactory diagnostic accuracy in differentiating bacterial infections in patients with all causes of liver cirrhosis in the ED. A cutoff value of 0.5 ng/mL is suggested for clinical use. ACADEMIC EMERGENCY MEDICINE 2011; 18:122-126 (C) 2011 by the Society for Academic Emergency Medicine