Outcomes in patients tested for Clostridium difficile toxins.

Clostridium difficile testing is shifting from toxin detection to C. difficile detection. Yet, up to 60% of patients with C. difficile by culture test negative for toxins and it is unclear whether they are infected or carriers. We reviewed medical records for 7046 inpatients with a C. difficile toxin test from 2005 to 2009 to determine the duration of diarrhea and rate of complications and mortality among toxin-positive (toxin+) and toxin- patients. Overall, toxin- patients had less severe diarrhea, fewer diarrhea days, and lower mortality (P < 0.001, all comparisons) than toxin+ patients. One toxin- patient (n = 1/6121; 0.02%) was diagnosed with pseudomembranous colitis, but there were no complications such as megacolon or colectomy for fulminant CDI among toxin- patients. These data suggest that C. difficile-attributable complications are rare among patients testing negative for C. difficile toxins. More studies are needed to evaluate the clinical significance of C. difficile detection in toxin- patients.