The International Classification of Diseases, 9th Revision, Clinical Modification, is the American version of the international ICD-( designed for the classification of morbidity and mortality information for statistical purposes and for the indexing of hospital records by disease and operations, for data storage and retrieval. It is sponsored by WHO.
The Need for Improvement
For a number of years, there has been a growing need for a more efficient base for storage and retrieval of diagnostic data in the health field, particularly within the hospital environment. In 1950, the U.S. Public Health Service and the Veterans Administration began independent testing of the international Classification of Diseases for hospital indexing purposes. A New York hospital adopted the ICD-6th Revision, with some modifications, for its records department. Several years later, the Commission on Professional and Hospital Activities adopted ICD with similar modifications, for use in hospitals participating in the Professional Activity Study.
In 1966, the international conference for the revision of the ICD-8th Revision constructed the revision with hospital indexing in mind. With studies and input of consultants, the American Hospital Association and the U.S. Public Health Service, the ICD-8 was adopted and served as the basis for coding diagnostic data for both official morbidity and mortality statistics in the U.S.
In February 1977, the National Center for Health Statistics developed the Clinical Modification of the ICD-9 with the valuable aid of many professional associations. In January 1979, the ICD-9-CM, the American Version of the ICD-9 became a single system accepted as a tool for classifying morbidity data for indexing of medical records.
The current ICD-9-CM exceeds its predecessors in the number of codes provided, and provides greater specificity at the fifth digit level of detail. The fifth digits are not optional!
On April 1, 1989, the Catastrophic Coverage Act of 1988 made the use of the ICD-9-CM system on all Medicare claims mandatory.