Usefulness of serum procalcitonin and point-of-care multiplex PCR gastro-intestinal panel in acute diarrhoea or colitis in the emergency department.

Introduction: Acute infectious diarrhoea is one of the most common diseases worldwide. Procalcitonin (PCT) is useful for antibiotic stewardship in lower respiratory tract infections but has been poorly studied in infectious diarrhoea. Our objective is to describe the PCT concentrations according to diarrhoea aetiology.

Methods: This is a single-center prospective cohort study involving adults consulting the emergency department (ED) for an acute diarrhoea or colitis. Serum PCT was measured and a stool sample was tested with FilmArray® Gastro-Intestinal Panel. The primary endpoint is the PCT concentration according to each type of pathogen identified using Gastro-Intestinal-panel and/or stool cultures at ED admission.

Results: 125 patients were included: 80 had an acute infectious diarrhoea, 21 an acute colitis and 24 another illness causing diarrhoea. The median (interquartile ranges) PCT values (ng/ml) were 0.13 (0.08-0.28), 0.07 (0.06-0.54), 0.13 (0.09-0.26) and 0.05 (0.03-0.17), respectively if there was a bacteria (n = 41), parasite (n = 3), virus (n = 10) or no pathogen identified and 0.34 (0.13-1.03) if the diarrhoea was due to another illness (n = 24).

Conclusion: In patients admitted to the ED with an acute infectious diarrhoea or acute colitis, PCT remained low when a bacteria was identified. It may not be informative in current practice to guide antibiotic therapy.