HCUP Methods Series - Agency for Healthcare Research and Quality

Box 2—Examples of single-level CCS procedure categoriesDescriptionICD-9-CM procedure CCS categorycodes used to mapHeart valve procedures 3500 3501 3502 3503 3504 3510 433511 3512 3513 3514 3520 35213522 3523 3524 3525 3526 35273528 3596 3599Coronary artery bypass graft(CABG)3610 3611 3612 3613 3614 36153616 3617 3619 362 363 36313632 363944ICD-9-CM codes for the single-level procedure CCS categories are presented inAppendix B. The ICD-9-CM code assignments to each category are viewable in theaccompanying executable files that provide the crosswalk from ICD-9-CM procedurecodes to single-level CCS categories.Labels for the single-level CCS procedures are available in Appendix B1.Multi-level CCSThe multi-level CCS is a hierarchical system and is defined using both single-level CCSgroupings and ICD-9-CM codes. There are four levels in the multi-level diagnosis CCSand three levels in the multi-level procedure CCS. The first of the four levels in the multileveldiagnosis CCS is broken into 17 categories. Similarly, the first of the three levels inthe multi-level procedure CCS is also broken into 17 categories. These 17 categoriesbroadly group the single-level CCS and ICD-9-CM codes into 17 body systems (e.g.,“Diseases of the Circulatory System”). Note that multi-level CCS categories arecomprised of single-level CCS categories or ICD-9-CM codes. Construction of multilevelCCS requires that ICD-9-CM codes first be assigned to single-level CCS.Diagnosis CodesThe specificity of categories increases with the higher levels, such that second-levelcategories are more specific than first-level categories, third-level categories are morespecific than second-level categories, and fourth-level categories are more specific thanthird-level categories.The first-level categories are identified by one whole digit (1-17), second-level categoriesinclude 1 decimal point, third-level categories have 2 decimal places and fourth levelcategories have 3 decimal places.Box 3 provides an example of multi-level CCS for diagnoses, showing how single-levelCCS category 99 (from single-level CCS example in Box 1) is further subdivided into themore specific levels in the multi-level system.HCUP CCS 6/16/2004 6