ICD-9 Codes and Surveillance for Clostridium difficile–associated Disease

Abstract

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%.