Role of Procalcitonin in Infectious Gastroenteritis and Inflammatory Bowel Disease

Background and Aim We have evaluated procalcitonin (PCT) as a diagnostic marker for bacterial gastroenteritis (GE) and as a disease activity marker in inflammatory bowel disease (IBD) patients. Methods This was a prospective single-center study performed over a 1-year period. Venous blood samples were drawn from hospitalized patients with acute GE and tested for PCT, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and total white cell count (TWC); stools from the same patients were tested for standard pathogens. Venous blood samples from patients with IBD were tested for PCT, CRP, ESR, and platelet count. The PCT level was measured using an immunofluorescent assay, with normal being defined as < 0.5 ng/ml. Results The GE arm of study consisted of 81 patients, 18.5% of whom were diagnosed with bacterial GE. The PCT and CRP levels were good diagnostic markers of bacterial GE, with an area under the curve (AUC) of 0.727 [95% confidence interval (CI) 0.580-0.874] and 0.786 (95% CI 0.627-0.946), respectively. An elevated PCT < 0.5 ng/ml was associated with a 13-fold increased risk of renal impairment. The IBD arm of study consisted of 72 IBD patients. The PCT levels were not significantly different between active and inactive IBD in this patient cohort. Conclusion Our results indicate that PCT and CRP are comparably good diagnostic markers of bacterial GE but that PCT is not useful as in monitoring disease activity in patients with IBD.