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NIS Description of Data Elements
The NIS is set of longitudinal hospital inpatient databases included in the HCUP family. These databases are created by AHRQ through a Federal-State-Industry partnership.
DCCHPRn - Clinical Classifications Software: diagnosis classification
Documentation Sections:
General Notes
Uniform Values
State Specific Notes
General Notes

Clinical Classifications Software (CCS), formerly known as Clinical Classifications for Health Policy Research (CCHPR), consists of 260 diagnosis categories. This system is based on ICD-9-CM codes. All diagnosis codes are classified. All E-codes (External Causes of Injury and Poisoning) are combined into the last category, 260.

DCCHPRn is coded as follows:

  • DCCHPRn ranges from 1 to 260 if the diagnosis code (DXn) is valid by the HCUP criteria, which allows a six-month window (three months before and three months after) around the official ICD-9-CM coding changes (usually October 1), for anticipation of or lags in response to official ICD-9-CM coding changes.
  • DCCHPRn is missing (.), if there is no diagnosis code (DXn = " ").
  • DCCHPRn is set to invalid (.A), if the diagnosis code (DXn) is invalid (DXVn = 1).

DCCHPRn is retained (values 1-260) when a valid diagnosis is flagged as inconsistent with age or sex (DXVn = .C). For best results, use DCCHPRn only when the diagnosis is valid and consistent (DXVn = 0).

Beginning in the 1998 data, this data element is called DXCCSn.


Labels for CCS, formerly known as CCHPR, categories are provided as an ASCII file in HCUP Tools: Labels and Formats.


Formats to label CCS, formerly known as CCHPR, categories are documented in HCUP Tools: Labels and Formats. Both sixteen-and forty-character labels are available.

A format is also available to map CCS codes into a few broad classes of conditions based on ICD-9-CM chapters. These formats are also documented in HCUP Tools: Labels and Formats.

Uniform Values
VariableDescriptionValueValue Description
DCCHPRnClinical Classifications Software: diagnosis classification1-260CCS Diagnosis Codes
.No diagnosis code
.AInvalid diagnosis code
State Specific Notes

Internet Citation: HCUP NIS Description of Data Elements. Healthcare Cost and Utilization Project (HCUP). September 2008. Agency for Healthcare Research and Quality, Rockville, MD.
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Last modified 9/17/08