Management of patients with respiratory infections in primary care: procalcitonin, C-reactive protein or both?

Use of inflammatory biomarkers to guide antibiotic decisions has shown promising results in the risk-adapted management of respiratory tract infections, mainly in the inpatient setting. Several observational and interventional trials have investigated the benefits of procalcitonin (PCT) and C-reactive protein (CRP) testing in primary care. Both markers have shown promising results, although CRP is an inflammatory biomarker while PCT is more specific for bacterial infections. For CRP, point-of-care testing is widely established. Recently, sensitive point-of-care testing for PCT has also become available. A high-quality trial comparing these two markers for the management of patients in primary care is currently lacking. The aim of this paper is to review the existing literature investigating the use of PCT and CRP in primary care. The authors compare their performance for guiding antibiotic stewardship and analyze the cut-off values and endpoints to put these parameters into context in a low-acuity environment.