Evaluation of a best practice alert to reduce unnecessary Clostridium difficile testing following receipt of a laxative.

INTRODUCTION: This study examined the effect of an alert notifying providers ordering Clostridium difficile PCR when their patient received a laxative within 24 hours at four hospitals.

METHODS: All patients whose provider received the laxative alert when ordering C. difficile testing were examined.

RESULTS: Three hundred sixty-six patients had 483 alerts triggered, with 75% overridden. While 74% of patients had ≥2 bowel movements immediately pre-order, 33% of C. difficile tests were not performed due to no stool production post-order or laboratory rejection of formed stool. Of those with completed tests, 49% had ≤1 cardinal sign of C. difficile infection (CDI) and only 18% tested positive by PCR. There were no differences in frequency of CDI signs between the PCR-positive and PCR-negative patients.

CONCLUSIONS: C. difficile testing was common among patients receiving laxatives. Patients testing positive for C. difficile looked clinically similar to patients testing negative, suggesting a high false-positive rate.