Using administrative diagnostic data to assess the quality of hospital care. Pitfalls and potential of ICD-9-CM.

Diagnostic information within administrative data bases is generally in the form of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. The purpose of this article is to introduce ICD-9-CM, to review its strengths and limitations, and to suggest ways that it can be used through administrative files for assessing the quality of hospital care.