Fecal calprotectin concentrations in cancer patients with Clostridium difficile infection

Fecal calprotectin (fCPT) has been used as a surrogate marker for assessment of intestinal inflammation. We explore the utility of fCPT values as a diagnostic aid in cancer patients with suspected Clostridium difficile infection (CDI). A total of 232 stool specimens submitted for GeneXpert C. difficile PCR testing were included in the study. All specimens were tested for fCPT and toxin/GDH antigens. Clinical severity of CDI cases was determined by the IDSA/SHEA criteria. Significant differences of median fCPT values between CDI (n = 117, Median 183.6 μg/g) and non-CDI (n = 115, 145.6 μg/g, p = 0.006) patients were seen. In CDI patents, significantly lower fCPT values were found in patients with mild to moderate (n = 95, 182.1 μg/g) than those with severe and severe to complicated (n = 22, 218.5 μg/g, p = 0.014) scores, and among those that were toxin positive (n = 24, 200.2 μg/g) vs. toxin negative (n = 86, 182.8 μg/g, p = 0.044). Despite this overall trend, wide variations in fCPT values were found in all categories examined. A logistic regression analysis revealed that the fCPT values correlated independently with the severity of clinical manifestations (OR = 2.021, 95%CI = 1.132-3.608); however, it did not correlate with other clinical outcomes. Our study findings show that high fecal calprotectin levels correlate with toxin-positive and clinically severe CDI; however, wide variations in individual measurements preclude establishment of reliable cut-offs for routine diagnostic use in cancer patients.