Introduction: Promising results in relation to severity assessment and treatment of patients with community-acquired pneumonia (CAP) have recently been presented from the study of procalcitonin (PCT) levels in these patients.
Methods: A systematic search in PubMed and the Cochrane Library was conducted. Articles in English, German and Swedish were searched to investigate the role of PCT in adults with CAP.
Results: The most thoroughly studied topic is the prediction of complications and death during hospital stay. PCT has predictive properties comparable to those of the Pneumonia Severity Index and the CURB65 scoring systems, and it may represent an addition to these indices. Furthermore, PCT levels may indicate aetiology as patients with typical bacterial infection have higher PCT levels than patients with atypical and viral aetiologies. The literature also indicates that PCT can distinguish CAP from asthma and acute exacerbation of chronic obstructive pulmonary disease. Several studies and a meta-analysis have shown that administration of antibiotics according to a PCT algorithm in a hospital setting reduced the use of antibiotics with no evidence of an increased risk.
Conclusion: PCT should only be an adjunct to the clinical examination and should be regarded a prognostic rather than diagnostic factor. PCT may help to safely reduce anti-biotic use, but more research is required. Limitations of the present study include the heterogeneity of the literature with regard to setup and quality, differences in biochemical methods and diagnostic criteria of CAP and, finally, the risk of publication bias.