Biomarkers in community-acquired pneumonia.

A relevant problem in the management of pulmonary infections is the low specificity of clinical symptoms for the exact diagnosis and the need of antibiotic therapy. An ideal biomarker for bacterial pulmonary infections should allow a rapid diagnosis, have a prognostic value and facilitate therapeutic decision making. The two biomarkers currently needed in clinical use are C-reactive protein and procalcitonin. C-reactive protein is very unspecific and elevated in bacterial as well as viral infections. Today, procalcitonin is the best validated biomarker for pulmonary infections. In several interventional studies procalcitonin-guided therapy has proven to allow a significant reduction of duration and frequency of antibiotic therapy. However, for the evaluation of prognosis in community-acquired pneumonia, new cardiovascular biomarkers are superior compared with inflammatory markers, especially for the determination of long-term mortality. The combination of several biomarkers reflecting different pathophysiological pathways has the potential to improve the management of community-acquired pneumonia in the future.