Background: It is a challenge to diagnosis Clostridium difficile colitis.

Objectives: To determine, among patients who developed nosocomial diarrhea, whether serum procalcitonin (PCT) can distinguish between C. difficile toxin (CDT)-positive and CDT-negative patients.

Methods: This prospective study included 50 adults (>18 years) who developed diarrhea during hospitalization, 25 with a positive fecal test for CDT (study group) and 25 CDT negative (control group).

Results: Baseline demographic and underlying illnesses were similar in both groups. Duration of diarrhea was 6 ± 4 days and 3 ± 1 in the study and control groups, respectively (P = 0.001). Mean blood count was 20 ± 15 and 9.9 ± 4, respectively (P = 0.04). CRP level was higher in the study than in the control group (10.9 ± 7.4 and 6.6 ± 4.8, P = 0.028). PCT level was higher in the study group (4.4 ± 4.9) than the control group (0.3 ± 0.5, P = 0.102). A PCT level > 2 ng/ml was found in 7/25 patients (28%) and 1/25 (4%), respectively [odds ratio 9.33, 95% confidence interval (0.98 to 220), P = 0.049]. Multivariate analysis showed that only duration of diarrhea and left shift of peripheral leucocytes were significant indicators of CDT (P = 0.014 and P = 0.019, respectively). The mortality rate was 12/25 (48%) vs. 5/25 (20%), respectively (P = 0.04).

Conclusions: We found a non-significant tendency to higher PCT levels in patients with CDT-positive vs. CDT-negative nosocomial diarrhea. However, a PCT level > 2 ng/ml may help distinguish between these patients.