What cardiologists do need to know about procalcitonin

This review will highlight the potential application of procalcitonin, a novel marker of systemic bacterial infection, in two clinical settings relevant to cardiologists: infective endocarditis (IE) and lower respiratory tract infections (LRTI): The variability in the clinical presentation of infective endocarditis (IE) makes the diagnosis a clinical challenge. However, rapid diagnosis and initiation of effective treatment are essential to good patient outcome. Serum calcitonin precursor levels, including procalcitonin, are elevated in systemic bacterial infections and seem to be helpful in the diagnosis of IE. The utility of procalcitonin in clinical practice was examined in a prospective cohort of patients with the suspicion of IE. Procalcitonin was significantly higher in patients with IE (median 6.56 microg/L) as compared with patients with other final diagnoses (median 0.44 microg/L, p or =0.5 or < or =0.25 microg/L), respectively. Final diagnoses included pneumonia (36%), acute exacerbation of COPD (25%), and acute bronchitis (24%). Clinical and laboratory outcome was similar in both groups and favourable in 96.7%. In the procalcitonin group, the adjusted relative risk of antibiotic exposure was 0.49 (p > 0.001), as compared to the standard group. Thus, using a sensitive assay, procalcitonin-guidance substantially and safely reduced antibiotic usage in LRTI.