CARIN Consumer Directed Payer Data Exchange (CARIN IG for Blue Button®)
1.0.0 - STU1

CARIN Consumer Directed Payer Data Exchange (CARIN IG for Blue Button®), published by HL7 Financial Management Working Group. This is not an authorized publication; it is the continuous build for version 1.0.0). This version is based on the current content of and changes regularly. See the Directory of published versions

ValueSet: MS-DRGs - AP-DRGs - APR-DRGs


Defining URL:
Title:MS-DRGs - AP-DRGs - APR-DRGs
Status:Active as of 2020-11-23T16:49:10+00:00

This value set defines three sets of DRGs, MS-DRGs (Medicare Severity Diagnosis Related Groups), APR-DRGs (All Patient Refined Diagnosis Related Groups) and AP-DRGs (All Patient Diagnosis Related Groups). Identifying a DRG code requires a version.


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 25 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).

Content can be obtained on the CMS hosted page located here


3M APR DRGs have become the standard across the U.S. for classifying hospital inpatients in non-Medicare populations. As of January 2019, 27 state Medicaid programs use 3M APR DRGs to pay hospitals, as do approximately a dozen commercial payers and Medicaid managed care organizations. Over 2,400 hospitals have licensed 3M APR DRGs to verify payment and analyze their internal operations.

The 3M APR DRG methodology classifies hospital inpatients according to their reason for admission, severity of illness and risk of mortality.

Each year 3M calculates and releases a set of statistics for each 3M APR DRG based on our analysis of large national data sets. These statistics include a relative weight for each 3M APR DRG. The relative weight reflects the average hospital resource use for a patient in that 3M APR DRG relative to the average hospital resource use of all inpatients. Please note that payers and other users of the 3M APR DRG methodology are responsible for ensuring that they use relative weights that are appropriate for their particular populations. The 3M APR DRG statistics also include data for each 3M APR DRG on relative frequency, average length of stay, average charges and incidence of mortality.

3M APR DRGs can be rolled up into broader categories. The 326 base DRGs roll up into 25 major diagnostic categories (MDCs) plus a pre-MDC category. An example is MDC 04, Diseases and Disorders of the Respiratory System. As well, each 3M APR DRG is assigned to a service line that is consistent with the outpatient service lines that are defined by the 3M™ Enhanced Ambulatory Patient Groups (EAPGs).

Link to information about the code system - including how to obtain the content from 3M - is available here..


In 1987, the state of New York passed legislation instituting a DRG-based prospective payment system for all non-Medicare patients. The legislation included a requirement that the New York State Department of Health (NYDH) evaluate the applicability of the DRGs to a non-Medicare population. In particular, the legislation required that the DRGs be evaluated with respect to neonates and patients with Human Immunodeficiency Virus (HIV) infections. NYDH entered into an agreement with 3M HIS to assist with the evaluation of the need for DRG modifications as well as to make the necessary changes in the DRG definitions and software. The DRG definitions developed by NYDH and 3M HIS are referred to as the All Patient DRGs (AP DRGs).

The AP DRG code system is no longer updated as DRG classification system evolved to APR DRG. Evolution of DRG is summarized in the APR DRG methodology overview as well as in various articles.

Goldfield N. The evolution of diagnosis-related groups (DRGs): from its beginnings in case-mix and resource use theory, to its implementation for payment and now for its current utilization for quality within and outside the hospital. Qual Manage Health Care. 2010;19(1)3-16.

Averill RF, Goldfield NI, Muldoon J, Steinbeck BA, Grant TM. A closer look at All-Patient Refined DRGs. J AHIMA. 2002;73(1):46-49.

Publisher:HL7 Financial Management Working Group

The Centers for Medicare & Medicaid Services (CMS) maintain MS-DRGs used throughout the US health care industry. The CMS MS-DRGs are free to use without restriction.

The clinical logic is maintained by a team of 3M clinicians, data analysts, nosologists, programmers and economists. The logic is proprietary to 3M but is available for licensees to view in an online definitions manual.

To license APR DRG from 3M, see request form here

Source Resource:XML / JSON / Turtle


Logical Definition (CLD)

This value set includes codes based on the following rules:



This value set contains 0 concepts


Explanation of the columns that may appear on this page:

Level A few code lists that FHIR defines are hierarchical - each code is assigned a level. In this scheme, some codes are under other codes, and imply that the code they are under also applies
Source The source of the definition of the code (when the value set draws in codes defined elsewhere)
Code The code (used as the code in the resource instance)
Display The display (used in the display element of a Coding). If there is no display, implementers should not simply display the code, but map the concept into their application
Definition An explanation of the meaning of the concept
Comments Additional notes about how to use the code