Value of procalcitonin in differentiating pulmonary tuberculosis from other pulmonary infections: a meta-analysis

To systematically and quantitatively summarise the current evidence on the utility of the procalcitonin test (PCT) in discriminating pulmonary tuberculosis (TB) from other pulmonary infections.

We searched MEDLINE, EMBASE and the Cochrane database up to August 2013 for studies that reported the performance of PCT alone or compared with other biomarkers in diagnosing pulmonary TB. We summarised PCT using forest plots, hierarchical summary receiver operating characteristic curves and bivariate random effects models.

We found nine qualifying studies covering 951 episodes of suspected TB along with 426 confirmed TB cases. The bivariate pooled sensitivity and specificity of PCT to distinguish TB from non-TB were respectively 42% (95%CI 30-56) and 87% (95%CI 63-96). The bivariate pooled sensitivity and specificity for PCT in distinguishing TB from bacterial pneumonia were respectively 78% (95%CI 67-86) and 85% (95%CI 78-90). Low heterogeneity was noted in studies comparing TB with bacterial pneumonia patients.

The results suggest consistently acceptable sensitivity and specificity of the PCT test in distinguishing TB from bacterial pneumonia. However, given the imperfect sensitivity and specificity of the test, medical decisions should be based on both the PCT test results as well as on clinical findings.