Searching for a Potential Algorithm for Clostridium difficile Testing at a Tertiary Care Hospital: Does Toxin Enzyme Immunoassay Testing Help?

Clostridium difficile is a major contributor to morbidity and mortality in the United States. Methods for identifying the organism in stool include molecular platforms, enzyme immunoassays (EIAs) for toxin, and culture. Controversy persists over whether molecular tests are too sensitive at identifying C. difficile, and there are questions about how additional laboratory information could inform clinical management and reduce over treatment. The aim of this study was to assess whether clinical factors are related to the toxin status of patients and whether information about toxin status could potentially inform clinical management of patients. A total of 201 PCR-positive C. difficile stool samples from adult patients at our institution underwent EIA toxin testing. Clinical and laboratory data were collected, and the percentage of PCR-positive/EIA-positive (PCR+/EIA+) patients and PCR+ and EIA-negative (PCR+/EIA-) patients was calculated. Of the 201 samples, 47% were EIA positive and 53% were EIA negative. Although PCR+/EIA+ patients were more likely to have had a prior C. difficile infection (P = 0.015), there was no statistical difference between the additional data collected that correlated with a positive EIA result. We were unable to show that patients with an EIA+ result had worse clinical parameters than those with EIA- results and concluded that establishing a testing algorithm that included both PCR and EIA testing would not change the clinical management of patients at our hospital.