Implementation of a Checklist to Reduce False-Positive Testing in Hospital-Acquired Clostridium Difficile Infection

Clostridium difficile is a major pathogen responsible for nosocomial infectious diarrhea. After a spike in Clostridium difficile infection (CDI) cases, the focus team identified several cases of inappropriate sampling, i.e., asymptomatic patients being tested. We hypothesized that the inappropriate samples were leading to a high number of false-positive cases. We explored appropriate patient stool sampling as a strategy for reducing the number of asymptomatic cases in a 275-bed rural community hospital.

We conducted a prospective cohort study of inpatients to determine if appropriate stool sampling would result in a reduction in false positive Clostridium difficile cultures and decrease incidence of Clostridium difficile. We developed a checklist that would guide the nurse to improve the sampling process.

The study implementation period ran from July through December 2016, with comparison to a control cohort in the prior six months. From Jan. 16 to May 15, the control group consisted of 461 inpatients, of which 89 tested positive for CDI 32.3 per 10,000 patient days. Of those 89 positive cases, 74 were identified as healthcare acquired infection (HAI) 26.8 per 10,000 patient days. Of these HAIs, 25 (33.8 percent) were inappropriate samples. In comparison, among the study period cohort of 277 inpatients, 46 inpatients tested positive for CDI 16.9 per 10,000 patient days, of which 26 were HAIs 9.5 per 10,000 patient days. During the study period, three samples (11.5 percent) were determined to be inappropriate. After the checklist implementation, the proportion of incorrect samples decreased from 33.8 percent to 11.5 percent. The number of HAI/patient days decreased form 0.024 percent to 0.08 percent. Similarly, the number of CDI/patient days also decreased from 0.295 percent to 0.15 percent.

Implementation of a simple checklist prior to collection of stool sample proved to be effective in reducing the number of inappropriate samples sent for CDI testing, with a subsequent decrease in hospital acquired Clostridium difficile infections reported.