Procalcitonin as a biomarker of infectious diseases.

Traditional biomarkers, including C-reactive protein, leukocytes, erythrocyte sedimentation rate, and clinical signs and symptoms, are not sufficiently sensitive or specific enough to guide treatment decisions in infectious febrile diseases. Procalcitonin (PCT) is synthesized by a large number of tissues and organs in response to invasion by pathogenic bacteria, fungi, and some parasites. A growing body of evidence supports the use of PCT as a marker to improve the diagnosis of bacterial infections and to guide antibiotic therapy. Clinically, PCT levels may help guide the need for empirical antibiotic therapy, source control for infections, and duration of antibiotic therapy. The aim of this review is to summarize the current evidence for PCT in different infections and clinical settings, and to discuss the reliability of this marker in order to provide physicians with an overview of the potential for PCT to guide antibiotic therapy.