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Clinical Classifications Software (CCS) Software and User's Guide


The Clinical Classifications Software (CCS) combines and aggregates codes from the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) into groups that can be employed in many types of projects analyzing data on diagnoses and procedures. The CCS tool is continually updated.

The CCS consists of the following classification systems:
  • Single-level CCS: Groups diagnoses into mutually exclusive categories. The single-level diagnosis CCS aggregates illnesses and conditions into 285 mutually exclusive categories. The single-level procedure CCS aggregates procedures into 231 mutually exclusive categories, most of which are homogeneous.
  • Multi-level CCS: Groups single-level CCS categories into broader categories (e.g., Infectious Disease, Mental Disorders, and Injury). It also splits single-level CCS categories to provide more detail about particular groupings of codes.

The CCS can be used to:

  • Identify cases for disease-specific or procedure-specific studies
  • Gain a better understanding of an institution's or health plan's distribution of patients across disease or procedure groupings
  • Provide statistical information on characteristics, such as changes and length of stay, about relatively specific conditions
  • Cross-classify procedures by diagnoses to provide insight into the variety of procedures performed for particular diagnoses
Links to the Tool:
This tool is available at:


Agency for Healthcare Research and Quality

Funding Sources

Agency for Healthcare Research and Quality

QualityTool Topic


Related Resources


  • Release Date: 02/2003
  • Review Date: 10/2011
  • Recent Summary: 12/2011
  • Original Summary: 11/2003
Disclaimer: The inclusion of a tool in the Innovations Exchange does not constitute or imply an endorsement by the U.S. Department of Health and Human Services, the Agency for Healthcare Research and Quality or Westat of the tool or of the submitter or developer of the tool. Read more.

Last updated: December 07, 2011.