Diagnosis-related Group - CMS DRG Version 25 Revision

CMS DRG Version 25 Revision

As of October 1, 2007, with version 25, the CMS DRG system resequenced the groups, so that for instance "Ungroupable" is no longer 470 but is now 999. To differentiate it, the newly resequenced DRG are now known as MS-DRG.

Before the introduction of version 25, many CMS DRG classifications were "paired" to reflect the presence of complications or comorbidities (CCs). A significant refinement of version 25 was to replace this pairing, in many instances, with a trifurcated design that created a tiered system of the absence of CCs, the presence of CCs, and a higher level of presence of Major CCs. As a result of this change, the historical list of diagnoses that qualified for membership on the CC list was substantially redefined and replaced with a new standard CC list and a new Major CC list.

Another planning refinement was not to number the DRGs in strict numerical sequence as compared with the prior versions. In the past, newly created DRG classifications would be added to the end of the list. In version 25, there are gaps within the numbering system that will allow modifications over time, and also allow for new MS-DRGs in the same body system to be located more closely together in the numerical sequence.