Clinical Utility and Measurement of Procalcitonin

Abstract

Procalcitonin (PCT), regarded as a biomarker specific for bacterial infections, is used in a variety of clinical settings including primary care, emergency department and intensive care. PCT measurement aids in the diagnosis of sepsis and to guide and monitor antibiotic therapy. This article gives a brief overview of PCT and its use in guiding antibiotic therapy in various clinical settings, as well as its limitations. PCT performance in comparison with other biomarkers of infection in particular CRP is also reviewed. Owing to its greater availability, CRP has been widely used as a biomarker of infection and sepsis. PCT is often reported to be more superior to CRP, being more specific for sepsis and bacterial infection. PCT starts to rise earlier and returns to normal concentration more rapidly than CRP, allowing for an earlier diagnosis and better monitoring of disease progression.

Figure 1.

Schematic diagram of PCT molecule and of its constituent peptide. Commercially available PCT assays recognise PCT and CT:CCP-1 forms. Adapted from Schneider and Lam 2007.

Figure 2a.

Age specific 95% reference range for PCT in healthy neonates. Figure 2b. PCT values obtained for patients with early onset infection within 48 h of age. The squares represent single values; dotted lines represent lower and upper limits of reference range, the bold represents the geometric mean. Reproduced from Cheisa C, Reliability of procalcitonin concentrations for the diagnosis of sepsis in critically ill neonates, Clin Infect Dis, 1998;26:664–72, by permission of Oxford University Press.

Figure 3.

Algorithms for initiating and discontinuing antibiotic therapy in ICU. Reprinted from The Lancet, 375, Bouadma L et al, Use of procalcitonin to reduce patients’ exposure to antibiotics in intensive care units (PRORATA trial): a randomised, controlled, open-label trial, pages 463–74, 2010, with permission from Elsevier.