How the MS-DRG Grouper Is Validated Against CMS Test Claims

Every MS-DRG this site assigns should match the one CMS would assign. To check that it does, we run CMS's published test claims through our grouper and compare each result with the answer CMS publishes.

1,817 / 1,817

CMS test claims grouped to the same MS-DRG that CMS expects, across 5 grouper versions.

Last run 2026-10-13

The test

CMS publishes a test database of 9,864 claims, each with the MS-DRG that CMS expects. CMS writes the expected answers, not us. We group each claim under the latest grouper release for its discharge fiscal year (for example, V41.1 for FY 2024), which is what CMS's expected answers use, and count the matches. That is why only one release per year appears below.

Grouper version	Claims	Match CMS
V40.1	380	380
V41.1	377	377
V42.1	222	222
V43.1	767	767
V44.0	71	71

Not compared: 7,905 claims (80% of the deck) are FY 2022 and earlier, which this site does not offer, plus 140 claims where CMS's expected result is a rejection rather than a DRG and 2 records with a damaged code in CMS's file.

Check it yourself

A sample of claims from the deck. Load fills in the grouper with the claim and its version, so you can run it and compare with CMS's answer. These are CMS test claims, built to exercise the grouping logic, so some look clinically odd.

Claim	Codes	CMS expects
V40.1 Discharged 04/01/2023 38M · status 01 DRG 981 Extensive O.R. procedures unrelated to principal diagnosis with MCC Load	I10 PDx A064 POA N 0SPT4JZ proc 0SRV0JZ proc	DRG 981 Extensive O.R. procedures unrelated to principal diagnosis with MCC	Load
V40.1 Discharged 10/01/2022 0M · status 01 DRG 794 Neonate with other significant problems Load	Z3800 PDx P9683 POA Y A064 POA Y	DRG 794 Neonate with other significant problems	Load
V40.1 Discharged 04/01/2023 38M · status 01 DRG 461 Bilateral or multiple major joint procedures of lower extremity with MCC Load	B902 PDx A064 POA N 0SPT4JZ proc 0SRV0JZ proc 0SPD0JZ proc 0SRD0J9 proc	DRG 461 Bilateral or multiple major joint procedures of lower extremity with MCC	Load
V41.1 Discharged 10/01/2023 55M · status 01 DRG 983 Extensive O.R. procedures unrelated to principal diagnosis without CC/MCC Load	E6601 PDx K6811 POA N 02HK3KZ proc	DRG 983 Extensive O.R. procedures unrelated to principal diagnosis without CC/MCC	Load
V41.1 Discharged 04/01/2024 40M · status 01 DRG 837 Chemotherapy with acute leukemia as secondary diagnosis or with high dose chemotherapy agent with MCC Load	Z08 PDx C9100 POA Y A021 POA Y	DRG 837 Chemotherapy with acute leukemia as secondary diagnosis or with high dose chemotherapy agent with MCC	Load
V41.1 Discharged 10/01/2023 55M · status 01 DRG 060 Multiple sclerosis and cerebellar ataxia without CC/MCC Load	G35 PDx G116 POA Y	DRG 060 Multiple sclerosis and cerebellar ataxia without CC/MCC	Load
V42.1 Discharged 10/01/2024 25M · status 01 DRG 003 ECMO or Tracheostomy with MV >96 Hours or Principal Diagnosis Except Face, Mouth and Neck with Major O.R. Procedures Load	A360 PDx 071B4Z7 proc 0B110F4 proc 5A1955Z proc	DRG 003 ECMO or Tracheostomy with MV >96 Hours or Principal Diagnosis Except Face, Mouth and Neck with Major O.R. Procedures	Load
V42.1 Discharged 10/01/2024 25M · status 01 DRG 175 Pulmonary Embolism with MCC or Acute Cor Pulmonale Load	I2604 PDx I2609 POA Y A021 POA Y	DRG 175 Pulmonary Embolism with MCC or Acute Cor Pulmonale	Load
V42.1 Discharged 10/01/2024 42M · status 01 DRG 264 Other Circulatory System O.R. Procedures Load	A3681 PDx 0DBN4ZX proc	DRG 264 Other Circulatory System O.R. Procedures	Load
V43.1 Discharged 10/01/2025 25M · status 01 DRG 008 Simultaneous Pancreas and Kidney Transplant Load	I120 PDx E0800 POA Y A021 POA Y 0TY00Z0 proc 0FYG0Z0 proc	DRG 008 Simultaneous Pancreas and Kidney Transplant	Load
V43.1 Discharged 10/01/2025 25M · status 01 DRG 082 Traumatic Stupor and Coma >1 Hour with MCC Load	S020XXA PDx S061X3A POA Y A021 POA Y	DRG 082 Traumatic Stupor and Coma >1 Hour with MCC	Load
V43.1 Discharged 10/01/2025 25M · status 01 DRG 466 Revision of Hip or Knee Replacement with MCC Load	T8451XA PDx A064 POA Y 0SP90JZ proc 0SR9019 proc	DRG 466 Revision of Hip or Knee Replacement with MCC	Load
V44.0 Discharged 10/01/2026 25M · status 01 DRG 010 Pancreas or Islet Cell Transplant Load	E083522 PDx A064 POA Y 0FYG0Z2 proc	DRG 010 Pancreas or Islet Cell Transplant	Load

How we check the grouper against CMS

The test

Check it yourself

What this does not cover