What CMS left undocumented in MS-DRGs – part 2

Just over a month into the new MS-DRG grouping methodologies, and there are still a lot of unknowns. In part two of my undocumented series, I would like to talk about MDC 3, where there is another large issue that is undocumented by CMS. This MDC—Ear, Nose, Mouth & Throat Conditions—has been the source of a lot of misinformation, inaccuracies and downright incorrect documentation.

Many of you may have read the final (and proposed rule) and seen the DRG consolidation table. The image below is directly from that table and it states that V24 DRGs 56-63 were combined into MS-DRGs 131, 132.

But in looking at the crosswalk that CMS published, you find a completely different story. The image below is taken from that crosswalk. It shows nothing crossing into MS-DRG 131, 132 and V24 DRGs 52, 55-63 crosswalking into MS-DRGs 133, 134.

The problem is that neither of these are completely correct. So, with some graphics, let me show you what really happened. In the first graphic below on the left-hand side are all the surgical V24 DRGs (in their hierarchy from first checked to last checked) for MDC 03. On the right hand side is the surgical MS-DRGs in their hierarchy for MDC 03.

First, let’s look at the easy part of the changes. In the graphic below, the black solid arrows represent where the procedures from V24 DRGs go in the new system. One can see that all the procedures in V24 DRG 049 map over to MS DRG 129/130. Similarly all the procedures for V24 DRG 061/062 map over to MS-DRGs 135/136. But, note the downward arrow. This means that these procedures have dropped in the surgical hierarchy and now will be considered AFTER procedures that occur before them in the surgical hierarchy. You can see that all the procedures for V24 DRG 168/169 map directly over to MS DRG 137/138, but have a similar drop in the surgical hierarchy. Finally, all the procedures for V24 DRG 050, 051 are combined into MS-DRG 139 (this was a documented consolidation).

In the next picture I’ve taken the first set of solid black lines and made them light gray so you can focus on the next step. The solid line in this new picture means that ALL the procedures have moved into the new DRG. The dotted line means that only some of the procedures have moved into the new DRG. We see that ALL the procedures from V24 061/062, 057/058, 052, 056, and 059/060 move into MS-DRG 133/134, but only some of the procedures from V24 055, and 063 move into MS-DRG 133/134. For many of these procedures, including the T&A onlys (59/60) and Misc and Other (055, 063), this is a major jump in the surgical hierarchy. This is close to what the CMS crosswalk says, but it doesn’t tell the entire story.

In the next illustration, the previous step is dimmed so we can focus on this step. Here we see what happened to the rest of the procedures in V24 DRG 55, 63. These procedures have been moved into the new MS-DRG 131/132.

If that was the end of the story maybe it wouldn’t be so bad. But upon a closer look at the new MS DRG 131/132, we find there is a list of procedures making up the criteria for these DRGs there that were NOT part of MDC 03 procedures in V24. This is visually represented in the picture below. Again, this is something that was not documented in the CMS literature, but we felt it important to let people know about.

A few very important points:

1. The increase in the surgical hierarchy for the Misc and Other procedures seems very strange. In the past, these procedures have been at the bottom of the surgical hierarchies. Moving them up may produce some undesirable effects. However, most of the procedures are typically low volume.
2. Moving the non-MDC 03 procedures into MDC 03 will cause some changes. Cases that previously would have grouped into DRG 468, Procedure Unrelated to Principal Diagnosis, will no longer group into the unrelated DRGs in MS-DRGs. This is probably a good thing, and is something that CMS should look to expand on where it can, as it will be more conducive to group these patients into like categories.

I would like to conclude with the lists of codes that are in each of these categories. First is the list of codes in V24 DRG 055 and the DRG that they correspond to under MS-DRGs . Second is list of codes in V24 DRG 063 and what DRG they are under in MS-DRGs . Finally, is the list of codes that were not part of MDC 03 procedures in V24 that ARE part of MDC 03 procedures under MS-DRGs .

Stay tuned for the next post.