Differentiating Clostridium difficile Colitis from Clostridium difficile Colonization in Ulcerative Colitis: A Role for Procalcitonin.

BACKGROUND/AIMS: Clostridium difficile infection (CDI) frequently complicates ulcerative colitis (UC) and can mimic disease flare. Differentiating UC flare from CDI remains a clinical challenge, particularly due to C. difficile colonization. Procalcitonin (PCT) is a serum biomarker for bacterial infections. We hypothesized that PCT would differentiate acute CDI from UC flare and C. difficile colonization. METHODS: A single-center prospective cohort study was conducted from 2013 to 2016. All UC patients with a stool sample for C. difficile testing were eligible. A total of 117 patients were enrolled, while 20 were excluded. Chart review was performed. RESULTS: Among 27 patients with CDI, median PCT was 60.7 (range 26-560.6) pg/mL, while among 90 patients without CDI, median PCT was 56.7 (range 25.1-2,252) pg/mL (p = 0.9). It was found that 14 patients with CDI responded completely to C. difficile treatment (CDI-R), while 8 patients did not and were diagnosed with UC flare (CDI-NR). For CDI-R, median PCT was 104.5 (range 26.3-560.6), compared to 40.3 (range 26.0-116.3) for CDI-NR (p = 0.036). CONCLUSIONS: In UC patients presenting with diarrhea, serum PCT was not significantly higher in UC patients with positive C. difficile testing. However, PCT was significantly elevated in CDI-R versus CDI-NR, suggesting that PCT may have utility in making this discrimination.