Hi @jweave17. My impression is that all DRG information should be stored in the Cost table. The concept_id for the DRG should be stored in the cost.drg_concept_id field. It looks like the domainid was not update to the cost table designation in the most recent vocabularies.
However, I believe the cost table only stores one DRG per cost, though I don't think that will be an issue for you. The MS-DRG-MDC code is just a category that the MS-DRG is located in. So I'm not sure why you want to add the MS-DRG-MDC information into the CDM - seems like duplication. AP-DRGs are codes associated with non-Medicare patients and MS-DRG codes are associated with Medicare patients. So you shouldn't get both codes for one patient. SO really there should only be one DRG code (regardless of type) for one inpatient bill. But if you are going to store the APR-DRG in the Cost table, then the concept_id should have a domainid of "cost"...... well and we should really add the APR-DRG into the vocabularies.
This sounds like a job for @Christian_Reich