ICD-9 codes and surveillance for Clostridium difficile-associated disease

Emerg Infect Dis. 2006 Oct;12(10):1576-9. doi: 10.3201/eid1210.060016.


We conducted a retrospective cohort study to compare Clostridium difficile-associated disease rates determined by C. difficile-toxin assays and International Classification of Diseases, 9th Revision (ICD-9) codes. The correlation between toxin assay results and ICD-9 codes was good (K = 0.72, p<0.01). The sensitivity of the ICD-9 codes was 78% and the specificity was 99.7%.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacterial Toxins / analysis*
  • Clostridioides difficile / isolation & purification*
  • Clostridioides difficile / metabolism
  • Cohort Studies
  • Enterocolitis, Pseudomembranous / diagnosis*
  • Enterocolitis, Pseudomembranous / microbiology
  • Female
  • Humans
  • International Classification of Diseases*
  • Male
  • Middle Aged
  • Retrospective Studies
  • Sensitivity and Specificity


  • Bacterial Toxins