MS-DRG Classifications and Software

Background

Section 1886(d) of the Act specifies that the Secretary shall establish a classification system (referred to as DRGs) for inpatient discharges and adjust payments under the IPPS based on appropriate weighting factors assigned to each DRG.  Therefore, under the IPPS, we pay for inpatient hospital services on a rate per discharge basis that varies according to the DRG to which a beneficiary's stay is assigned. The formula used to calculate payment for a specific case multiplies an individual hospital's payment rate per case by the weight of the DRG to which the case is assigned.  Each DRG weight represents the average resources required to care for cases in that particular DRG, relative to the average resources used to treat cases in all DRGs.

Congress recognized that it would be necessary to recalculate the DRG relative weights periodically to account for changes in resource consumption.  Accordingly, section 1886(d)(4)(C) of the Act requires that the Secretary adjust the DRG classifications and relative weights at least annually.  These adjustments are made to reflect changes in treatment patterns, technology, and any other factors that may change the relative use of hospital resources.

Currently, cases are classified into Medicare Severity Diagnosis Related Groups (MS-DRGs) for payment under the IPPS based on the following information reported by the hospital: the principal diagnosis, up to 24 additional diagnoses, and up to 25 procedures performed during the stay.  In a small number of MS-DRGs, classification is also based on the age, sex, and discharge status of the patient.  Effective October 1, 2015, the diagnosis and procedure information is reported by the hospital using codes from the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) and the International Classification of Diseases, Tenth Revision, Procedure Coding System (ICD-10-PCS).

For additional information on the MS-DRG system, including yearly reviews and changes to the MS-DRGs, please view prior Inpatient Prospective Payment System (IPPS) proposed and final rules located in the left navigational area of this page.

Requests for annual MS-DRG classification changes and any MS-DRG related inquiries should be sent to the MSDRGClassificationChange@cms.hhs.gov mailbox. 

 

Latest News

ICD-10 MS-DRGs V39.1 Effective April 1, 2022  (ZIP) - Updated 11/16/2021

ICD-10 MS-DRGs V38.1 Effective January 1, 2021 (ZIP)

ICD-10 MS-DRGs Version 37.2 Effective August 01, 2020 (PDF)

July 2020 Quarterly Update to the Inpatient Prospective Payment System (IPPS) Fiscal Year (FY) 2020 Pricer (PDF)

ICD-10 MS-DRGs Version 37.1 R1 Effective April 1, 2020 - Updated March 23, 2020 (PDF)

ICD-10 MS-DRGs Version 37.1 Effective April 1, 2020 (PDF) 

 

MS-DRG CC/MCC Comprehensive Analysis Information

CMS hosted a listening session that described the Medicare-Severity Diagnosis-Related Group (MS‑DRG) Complication and Comorbidity (CC)/Major Complication and Comorbidity (MCC) Comprehensive Analysis discussed in the FY 2020 Inpatient Prospective Payment System (IPPS) proposed and final rules. This listening session included a review of the methodology to measure the impact on resource use and provided an opportunity for CMS to receive public input on this analysis and to address any clarifying questions in order to assist the public in formulating written comments on the current severity level designations for consideration in future rulemaking.

This listening session was held on October 8, 2019; 2:00 – 3:00 PM ET.

For the transcript and audio file of the listening session, visit https://www.cms.gov/Outreach-and-Education/Outreach/OpenDoorForums/Downloads/10082019ListingSessionTrasncriptandQandAsandAudioFile.zip.

Link to the supplementary file that was made available for the listening session:

We are providing updated impact on resource use files so that the public can review the mathematical data for the impact on resource use generated using claims from the FY 2019 - FY 2021 MedPAR files:

 

MS-DRG Definitions Manual and Software

FY 2023 – Version 40 Test GROUPER – DRAFT file for FY 2023 IPPS/LTCH PPS Proposed Rule

This is a supporting file for the FY 2023 IPPS/LTCH PPS Proposed Rule

We are providing a test version of the ICD-10 MS-DRG GROUPER Software, Version 40, so that the public can better analyze and understand the impact of the proposals included in the FY 2023 IPPS/LTCH PPS proposed rule. This test software reflects the proposed GROUPER logic for FY 2023.  For additional information regarding the Version 40 Test GROUPER please see the file titled CMS-1771-P Table 6P.1a below.

In addition, users are able to view the draft version of the ICD-10 MS-DRG Definitions Manual, Version 40.

  1. Proposed ICD-10 MS-DRG Definitions Manual Files V40 (ZIP): A zip file with the ICD-10 MS DRG Definitions Manual (Text Version) contains the complete documentation of the proposed ICD-10 MS-DRG Grouper logic.
  2. Proposed ICD-10-CM/PCS MS-DRG V40 Definitions Manual Table of Contents - Full Titles - HTML Version
  3. Medicare Severity Diagnosis Related Group (MS-DRG) Test Grouper Software and Medicare Code Editor (MCE) Version 40, ICD-10 PC Software (ZIP)
  4. CMS-1771-P Table 6P.1a (ZIP): An Excel file that contains the mapped Version 40 FY 2023 ICD-10-CM codes and the deleted Version 39.1 FY 2022 ICD-10-CM codes that should be used for testing purposes with users’ available claims data.

 

FY 2022 – Version 39.1 (Effective April 1, 2022 through September 30, 2022)

Update 3/14/22: We are providing a re-release of the version 39.1 software to reflect improvements made in the performance of the software and related test files.  These updates do not affect any testing or grouping results.

  • The Java Mainframe Software package has been enhanced with new logic to align the version of the MS-DRG Grouper that is called with the version of the MCE that is called, based on the discharge date.  Additional details are provided in the updated Mainframe install guide.
  • The Mainframe test databases were synchronized to address differences in claims dates across the legacy and Java implementations. 

We are also including the Java PC software package that was not initially displayed with version 39.1.

  1. Definition of Medicare Code Edits V39.1 (ZIP)  - Updated 3/14/22: The ICD-10 Definitions of Medicare Code Edits file contains the following: A description of each coding edit with the corresponding code lists as well as all the edits and the code lists effective for FY 2022. Zip file contains a PDF and text file that is 508 compliant.
  2. ICD-10 MS-DRG Definitions Manual Files V39.1 (ZIP)  - Updated 3/18/22: A zip file with the ICD-10 MS DRG Definitions Manual (Text Version) contains the complete documentation of the ICD-10 MS-DRG Grouper logic. 
  3. V39.1  Definitions Manual Table of Contents - Full Titles - HTML Versions - Updated 3/18/22
  4. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version V39.1  MAINFRAME Software (ZIP) -  Updated 3/14/22
  5. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version V39.1, ICD-10 PC Software (ZIP) -  Updated 3/14/22
FY 2022 – Version 39 (Effective October 1, 2021 through March 31, 2022)

Update 12/22/2021: The Apache Log4j open-source logging software library is used in the PC and Java based grouping and editing software (MS-DRG Java, MCE Java, MSGMCE). Recently, a vulnerability was discovered in Log4j that could present security issues when running under certain conditions. The Mainframe BAL software is not impacted.

Apache has issued an updated version of Log4j (2.16.0) to fix this issue. The updated software removes any potential association with the vulnerability.

There is no impact or change to any grouping or editing results or data files.

We have provided updated software files in order to remove any potential association with the vulnerability.

MS-DRG and MCE Mainframe Java distribution updates:

  • Removed Log4j from the MS-DRG Mainframe and MCE Mainframe Java software packages as this logging is not utilized in this environment
  • Updated the documentation for the standalone Java MS-DRG and MCE to reference 2.16.0 of Log4j

MSGMCE Products

  •  Updated the Log4j version used to 2.16.0 from the current versions (MSGMCE PC - 2.7)
  1.  Definition of Medicare Code Edits V39 (ZIP) :The ICD-10 Definitions of Medicare Code Edits file contains the following: A description of each coding edit with the corresponding code lists as well as all the edits and the code lists effective for FY 2022. Zip file contains a PDF and text file that is 508 compliant.  
  2. ICD-10 MS-DRG Definitions Manual Files V39 (ZIP): A zip file with the ICD-10 MS DRG Definitions Manual (Text Version) contains the complete documentation of the ICD-10 MS-DRG Grouper logic.  
  3. V39  Definitions Manual Table of Contents - Full Titles - HTML Versions 
  4. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version 39  MAINFRAME Software (ZIP)  - Updated 12/22/21 
  5. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version 39, ICD-10 PC Software (ZIP) - Updated 12/22/21
FY 2022 – V39 TEST GROUPER - DRAFT file for FY 2022 IPPS/LTCH PPS Proposed Rule

This is a supporting file for the FY 2022 IPPS/LTCH PPS Proposed Rule

We are providing a test version of the ICD-10 MS-DRG GROUPER Software, Version 39, so that the public can better analyze and understand the impact of the proposals included in the FY 2022 IPPS/LTCH PPS proposed rule. This test software reflects the proposed GROUPER logic for FY 2022. For additional information regarding the Version 39 Test GROUPER please see the file titled CMS-1752-P Tables 6P.1a and 6P.1b below.

In addition, users are able to view the draft version of the ICD-10 MS-DRG Definitions Manual, Version 39.

  1. Proposed ICD-10 MS-DRG Definitions Manual Files V39 (ZIP): A zip file with the ICD-10 MS DRG Definitions Manual (Text Version) contains the complete documentation of the proposed ICD-10 MS-DRG Grouper logic.
  2. Proposed ICD-10-CM/PCS MS-DRG V39 Definitions Manual Table of Contents - Full Titles - HTML Version
  3. Medicare Severity Diagnosis Related Group (MS-DRG) Test Grouper Software and Medicare Code Editor (MCE) Version 39, ICD-10 PC Software (ZIP)
  4. CMS-1752-P Table 6P.1a and 6P.1b (ZIP): An Excel file that contains the mapped Version 39 FY 2022 ICD-10-CM and ICD-10-PCS codes and the deleted Version 38 FY 2021 ICD-10-CM and ICD-10-PCS codes that should be used for testing purposes with users’ available claims data.
FY 2021 – Version 38.1 (Effective January 1, 2021 through September 30, 2021
  1. Definition of Medicare Code Edits V38.1 (ZIP): The ICD-10 Definitions of Medicare Code Edits file contains the following: A description of each coding edit with the corresponding code lists as well as all the edits and the code lists effective for FY 2021. Zip file contains a PDF and text file that is 508 compliant.
  2. ICD-10 MS-DRG Definitions Manual Files V38.1 (ZIP): A zip file with the ICD-10 MS DRG Definitions Manual (Text Version) contains the complete documentation of the ICD-10 MS-DRG Grouper logic. 
  3. V38.1  Definitions Manual Table of Contents - Full Titles - HTML Versions
  4. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version V38.1  MAINFRAME Software (ZIP)
  5. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version V38.1, ICD-10 PC Software (ZIP)
Java – Beta Version 38.1

The MS-DRG Java zip file has been updated to include a missing dependency required for testing. The MS-DRG Java API and calling example documentation has been updated to include references to this dependency as well as corrections to make method naming consist. The MS-DRG and MCE Java Mainframe deliverables have updated install guide PDF with corrections for clarity. There were no changes made to the functionality or content of MS-DRG or MCE.

Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Java Beta Version 38.1 MAINFRAME Software (ZIP) - UPDATED 5.24.21

Inquiries related to this Java Beta version of the Grouper should be directed to GrouperBetaTesting@cms.hhs.gov

 

FY 2021 – Version 38.0 R1 (Effective October 1, 2020 through December 31, 2020)

Errata (PDF): A document describing the changes from Version 38 to Version 38.0 R1

  1. Definition of Medicare Code Edits V38.0 R1 (ZIP)The ICD-10 Definitions of Medicare Code Edits file contains the following: A description of each coding edit with the corresponding code lists as well as all the edits and the code lists effective for FY 2021. Zip file contains a PDF and text file that is 508 compliant
  2. ICD-10 MS-DRG Definitions Manual Files V38.0 R1 (ZIP)A zip file with the ICD-10 MS DRG Definitions Manual (Text Version) contains the complete documentation of the ICD-10 MS-DRG Grouper logic. 
  3. V38.0 R1 Definitions Manual Table of Contents - Full Titles - HTML Versions 
  4. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version V38.0 R1 MAINFRAME Software (ZIP)
  5. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version V38.0 R1, ICD-10 PC Software (ZIP)
FY 2021 – V38 TEST GROUPER - DRAFT file for the FY 2021 IPPS/LTCH PPS Proposed Rule

This is a supporting file for the FY 2021 IPPS/LTCH PPS Proposed Rule 

We are providing a test version of the ICD-10 MS-DRG GROUPER Software, Version 38, so that the public can better analyze and understand the impact of the proposals included in the FY 2021 IPPS/LTCH PPS proposed rule. This test software reflects the proposed GROUPER logic for FY 2021.  For additional information regarding the Version 38 Test GROUPER please see the file titled CMS-1735-P Table 6P.1a below.

In addition, users are able to view the draft version of the ICD-10 MS-DRG Definitions Manual, Version 38. 

  1. Proposed ICD-10 MS-DRG Definitions Manual Files V38 (ZIP): A zip file with the ICD-10 MS DRG Definitions Manual (Text Version) contains the complete documentation of the proposed ICD-10 MS-DRG Grouper logic. 
  2. Proposed ICD-10-CM/PCS MS-DRG V38 Definitions Manual Table of Contents - Full Titles - HTML Version
  3. Medicare Severity Diagnosis Related Group (MS-DRG) Test Grouper Software and Medicare Code Editor (MCE) Version 38, ICD-10 PC Software (ZIP)
  4. CMS-1735-P Table 6P.1a (ZIP): An Excel file that contains the mapped Version 38 FY 2021 ICD-10-CM codes and the deleted Version 37 FY 2020 ICD-10-CM codes that should be used for testing purposes with users’ available claims data.
FY 2020 - Version 37.2 - (Effective August 1, 2020 through September 30, 2020) 
  1. Definition of Medicare Code Edits V37.2 (ZIP):The ICD-10 Definitions of Medicare Code Edits file contains the following: A description of each coding edit with the corresponding code lists as well as all the edits and the code lists effective for FY 2020. Zip file contains a PDF and text file that is 508 compliant.
  2. ICD-10 MS-DRG Definitions Manual Files V37.2 (ZIP): A zip file with the ICD-10 MS DRG Definitions Manual (Text Version) contains the complete documentation of the ICD-10 MS-DRG Grouper logic. 
  3. V37.2 Definitions Manual Table of Contents - Full Titles - HTML Versions
  4. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version 37.2  MAINFRAME Software (ZIP)   
  5. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version 37.2, ICD-10 PC Software (ZIP) 
FY 2020 - Version 37.1 R1– (Effective April 1, 2020 through July 31, 2020)
  1. Definition of Medicare Code Edits V37.1 R1 (ZIP): The ICD-10 Definitions of Medicare Code Edits file contains the following: A description of each coding edit with the corresponding code lists as well as all the edits and the code lists effective for FY 2020. Zip file contains a PDF and text file that is 508 compliant
  2. ICD-10 MS-DRG Definitions Manual Files V37.1 R1 (ZIP) : A zip file with the ICD-10 MS DRG Definitions Manual (Text Version) contains the complete documentation of the ICD-10 MS-DRG Grouper logic.  
  3. ICD-10-CM/PCS MS-DRG V37.1 R1 Definitions Manual Table of Contents - Full Titles - HTML Versions - UPDATED
  4. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version 37.1 R1  MAINFRAME Software (ZIP) 
  5. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version 37.1 R1, ICD-10 PC Software (ZIP)  (ZIP)
FY 2020 - Version 37 R1 (Effective October 1, 2019 through March 31, 2020)
  1. Definition of Medicare Code Edits v37 (ZIP) : The ICD-10 Definitions of Medicare Code Edits file contains the following: A description of each coding edit with the corresponding code lists as well as all the edits and the code lists effective for FY 2020. Zip file contains a PDF and text file that is 508 compliant.
  2. ICD-10 MS-DRG Definitions Manual Files v37 R1 (Updated September 19, 2019) (ZIP) : A zip file with the ICD-10 MS DRG Definitions Manual (Text Version) contains the complete documentation of the ICD-10 MS-DRG Grouper logic.
  3. ICD-10-CM/PCS MS-DRG v37 R1 Definitions Manual Table of Contents - Full Titles - HTML Versions-UPDATED - Opens in a new window  
  4. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper MAINFRAME Software and ERRATA, v37 R1 (Updated September 18, 2019) (ZIP)  
  5. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version 37, ICD-10 PC Software - Opens in a new window
FY 2019 - Version 36 (Effective October 1, 2018 through September 30, 2019)
  1. Definition of Medicare Code Edits v36 (ZIP) : The ICD-10 Definitions of Medicare Code Edits file contains the following: A description of each coding edit with the corresponding code lists as well as all the edits and the code lists effective for FY 2019. Zip file contains a PDF and text file that is 508 compliant.
  2. Errata and ICD-10 MS-DRG Definitions Manual Files v36 R1 (Updated October 09, 2018) (ZIP) : A zip file with the ICD-10 MS DRG Definitions Manual (Text Version) contains the complete documentation of the ICD-10 MS-DRG Grouper logic. 
  3. ICD-10-CM/PCS MS-DRG v36 R1 Definitions Manual Table of Contents - Full Titles - HTML Versions (Updated October 12, 2018)
  4. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version 36, ICD-10 Software - Opens in a new window  
FY 2018 - Version 35 (Effective October 1, 2017 through September 30, 2018)
  1. Definition of Medicare Code Edits v35 (ZIP) : The ICD-10 Definitions of Medicare Code Edits file contains the following: A description of each coding edit with the corresponding code lists as well as all the edits and the code lists effective for FY 2018. Zip file contains a PDF and text file that is 508 compliant.
  2. ICD-10 MS-DRG Definitions Manual Files v35 (Updated September 12, 2017) (ZIP) : A zip file with the ICD-10 MS DRG Definitions Manual (Text Version) contains the complete documentation of the ICD-10 MS-DRG Grouper logic.
  3. ICD-10-CM/PCS MS-DRG v35 Definitions Manual Table of Contents - Full Titles - HTML Versions (Updated September 13, 2017)
  4. Medicare Severity Diagnosis Related Group (MS-DRG) Grouper Software and Medicare Code Editor (MCE) Version 35 R1, ICD-10 Software (ZIP, 125MB) - Opens in a new window  

 

HCPCS-MS-DRG Definitions Manual and Software

The 21st Century Cures Act requires that by January 1, 2018, the Secretary develop an informational “HCPCS version” of at least 10 surgical MS-DRGs.  Under the HCPCS version of the MS-DRGs developed for this requirement, to the extent feasible, the MS-DRG assignment for a given service furnished to an outpatient (billed using a HCPCS code) is as similar as possible to the MS-DRG assignment for that service if furnished to an inpatient (billed using an ICD-10-PCS code).

The HCPCS-MS-DRG definitions manual and software developed under the requirements of section 15001 of the 21st Century Cures Act (Public Law 114–255). Questions about the posted HCPCS-MS-DRG definitions manual and software can be directed to HCPCS_MS_DRG@cms.hhs.gov.

Page Last Modified:
04/21/2022 09:58 AM