Serum procalcitonin and C-reactive protein levels as markers of bacterial infection in patients with liver cirrhosis: a systematic review and meta-analysis

The diagnostic value of procalcitonin (PCT) for patients with liver cirrhosis is unclear. We searched the PubMed, EMBASE, and Cochrane databases for studies published through December 2013 that evaluated the diagnostic performance of PCT for patients with acute or chronic liver disease with suspected systemic infection. We summarized the test performance characteristics by using forest plots, hierarchical summary receiver operating characteristic curves, and bivariate random effects models. Our search identified 230 citations, of which 10 diagnostic studies that evaluated 1144 patients and 435 bacterial infection episodes (32.1%) were ultimately included for analysis. The bivariate pooled sensitivity estimates were 79% (95% confidence interval [CI]: 64%-89%) for PCT tests and 77% (95% CI: 69%-84%) for C-reactive protein (CRP) tests. Pooled specificity estimates were higher for both PCT and CRP tests (PCT, 89% [95% CI: 82%-94%]; CRP, 85% [95% CI: 76%-90%]). The positive likelihood ratio for PCT (LR+, 7.38, 95% CI: 4.70-11.58) was sufficiently high to qualify PCT as a rule-in diagnostic tool, and the negative likelihood ratio for CRP was sufficiently low to qualify CRP as an acceptable rule-out diagnostic tool (LR− 0.23, 95% CI: 0.13-0.41) in patients with no signs of infection. Available clinical evidence showed that PCT has comparable accuracy to CRP for the diagnosis of systemic infection in patients with liver cirrhosis. Compared with patients with normal liver function, both PCT and CRP tests have acceptable accuracy for diagnosing bacterial infection among patients with liver cirrhosis.