Is DRG inpatient only?

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Yes, traditional Diagnosis-Related Groups (DRGs) are used exclusively for Acute Inpatient PPS hospital stays.

How DRGs Work

  • Inpatient Only: Under Medicare's Inpatient Prospective Payment System (IPPS), hospitals receive a fixed, predetermined flat payment for an admitted patient based on their Diagnosis-related group (DRG) upon discharge.
  • Facility vs. Outpatient: DRGs do not apply to outpatient care, emergency room visits that do not lead to an admission, or a doctor's individual professional fees.

Outpatient and Other Settings

  • Outpatient Payments: Outpatient services use different systems, such as Ambulatory Payment Classifications (APCs) under the Outpatient Prospective Payment System (OPPS), which pay for individual services rather than a bundled inpatient stay.
  • Alternative Models: While some modern experimental payment models bundle inpatient and outpatient care together, the classic DRG classification framework itself remains tied to inpatient hospital admissions.

Is DRG inpatient or outpatient?

A Diagnosis-Related Group (DRG) is exclusively used for inpatient hospital stays.

Inpatient vs. Outpatient Classification

  • Inpatient Care (DRG System): When a patient is formally admitted to a hospital, insurers (including Medicare through the Inpatient Prospective Payment System) use a bundled, fixed-rate payment based on the assigned DRG code. This payment covers the entire stay based on diagnosis and severity, rather than itemizing individual services.
  • Outpatient Care (APC/Fee-for-Service): Outpatient visits—such as same-day surgeries, emergency department care, or clinic visits—do not use DRGs. Instead, they typically rely on systems like Ambulatory Payment Classifications (APCs) or itemized CPT codes where each service is billed separately.

How does DRG billing work?

Diagnosis-related group (DRG) billing pays hospitals a single, fixed amount for an inpatient hospital stay based on the patient's diagnosis and medical procedures, rather than charging for each individual test or service.

How the DRG Process Works

  • Diagnosis and Treatment: Doctors treat the patient during an inpatient hospital stay.
  • Medical Coding: Medical coders review records and assign standard codes (like ICD codes) for the main diagnosis, other health conditions, and procedures.
  • DRG Assignment: Software groups these codes into a specific DRG category that reflects clinical similarity and expected resource use.
  • Payment Calculation: The payer (such as Medicare or private insurance) multiplies the DRG's assigned relative weight (measuring resource intensity) by the hospital's base payment rate to set the final reimbursement.

Key Factors in DRG Assignment

  • Principal Diagnosis: The main condition that caused the patient to be admitted.
  • Complications and Comorbidities (CCs/MCCs): Secondary conditions or major complications that increase the severity and raise the DRG payment tier.
  • Procedures: Surgical operations or treatments performed during the stay.
  • Patient Demographics: Age, sex, and discharge status.

Financial Impact

  • Profit or Loss: If a hospital treats a patient for less than the fixed DRG payment, it makes a profit. If the treatment costs more than the fixed amount, the hospital absorbs the loss.

Where can I find the CMS DRG list for 2026?

You can find the official FY 2026 Medicare Severity Diagnosis Related Group (MS-DRG) files and lists directly on the FY 2026 IPPS Final Rule Home Page.

Where to Access the Lists and Files

What are the different types of DRGs?

Diagnosis-Related Groups (DRGs) are classification systems used to group hospital inpatient stays into fixed payment categories based on diagnoses, procedures, and expected resource use.

The three primary overarching types of DRG systems include:

1. Basic DRGs (Standard DRGs)

  • Definition: The original classification system created for Medicare to determine standard inpatient hospital reimbursement.
  • Focus: Measures basic resource utilization and average costs for adult patient populations using one or two general levels of severity.

2. MS-DRGs (Medicare Severity DRGs)

  • Definition: An updated version used by Medicare that refines basic DRGs by factoring in patient severity levels.
  • Tiers: Splits codes based on CCs (Complications and Comorbidities) or MCCs (Major Complications and Comorbidities).
  • Purpose: Ensures hospitals receive higher payouts for more complex, sicker patients who require intensive care and resources.

3. AP-DRGs and APR-DRGs (All-Patient and All-Patient Refined DRGs)

  • AP-DRGs: Expanded versions designed for non-Medicare groups, including pediatric patients and newborns who are underrepresented in standard Medicare data.
  • APR-DRGs: Extends AP-DRGs by adding distinct subclasses for severity of illness and risk of mortality (rated from minor to extreme), making them useful for wider state data tracking and non-Medicare commercial insurance.

Internal Structure of DRG Categories

No matter the system used, DRGs are further divided into two main clinical paths:

  • Medical DRGs: For treatments managed without major operating room procedures.
  • Surgical DRGs: For cases requiring formal operations or invasive procedures.
  • Major Diagnostic Categories (MDCs): These divide cases into 25 distinct body systems or medical areas (such as circulatory, respiratory, or nervous system conditions).

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9 related questions found

Are DRG codes only for inpatient care?

Yes, Diagnosis-Related Group (DRG) codes are primarily used for inpatient hospital care, but they have minor exceptions or parallel systems in certain outpatient or bundled payment models.

How DRGs Work for Inpatient Care

  • Inpatient Prospective Payment System (IPPS): Medicare and most insurance companies use MS-DRGs (Medicare Severity Diagnosis-Related Groups) to pay acute care hospitals a fixed, bundled amount for an inpatient stay.
  • Patient Admission Required: A patient must be officially admitted to the hospital as an inpatient for a DRG to be assigned upon discharge.
  • Based on Clinical Data: The code depends on the principal diagnosis, secondary conditions, surgical procedures, age, and discharge status.

Outpatient and Other Exceptions

  • Outpatient Prospective Payment: Traditional outpatient visits (like standard clinic appointments or emergency room visits without an admission) use CPT codes and HCPCS codes rather than DRGs.
  • Specialty Facilities: Psychiatric hospitals, inpatient rehab units, and long-term care hospitals often use separate payment systems instead of standard acute-care MS-DRGs.
  • Bundled Payment Tests: Some modern insurance payment models test combining certain outpatient and inpatient services into a single bundled payment framework, but standard DRG assignment remains an inpatient staple.

What is the difference between a CPT code and a DRG code?

A CPT (Current Procedural Terminology) code describes a specific medical service or procedure performed by a provider, while a DRG (Diagnosis-Related Group) code bundles an entire inpatient hospital stay into a single category to determine a fixed payment.

Key Differences

  • Definition: CPT codes are 5-digit numbers that detail specific actions like tests, surgeries, or office visits. DRG codes are classification groups that combine a patient's diagnoses, procedures, age, and complications to categorize an overnight hospital stay.
  • Setting: CPT codes are used across all settings, including doctor offices, outpatient clinics, and hospitals. DRG codes are used strictly for inpatient hospital stays.
  • Billing and Payment: Individual physicians are paid based on individual CPT codes for the work they do. Hospitals receive one fixed, bundled payout based on a DRG code, no matter how many individual services or items the patient actually used during that stay.
  • Application: Every outpatient or professional service gets specific CPT codes. A DRG code is generated on the backend by software using a mix of CPT, ICD diagnosis codes, and other data to process the final hospital claim.

What are the disadvantages of DRGs?

Diagnosis-Related Groups (DRGs)—a system used by Original Medicare and other insurers to categorize hospital cases and provide fixed payments—carry several financial, clinical, and administrative disadvantages.

Clinical and Patient Care Risks

  • Early patient discharges: Hospitals have a financial incentive to discharge patients sooner because they receive a flat rate regardless of the actual length of stay.
  • Decreased care quality: Rushed discharges or reduced services can lead to higher rates of medical complications and increased patient readmissions.
  • Avoidance of complex cases: Providers may try to turn away or transfer severely ill patients or specialized cases that cost more than the standard fixed payment.
  • Reduced access to care: Facilities might cut back on specific high-cost services or limit overall patient admissions to protect their profit margins.

Financial and Administrative Burdens

  • Financial losses for hospitals: If treating a patient costs more than the assigned DRG flat rate, the hospital absorbs the loss.
  • Cost shifting: Institutions may shift financial burdens to other sectors, outpatient services, or push higher out-of-pocket costs onto patients.
  • Coding and downcoding vulnerability: Errors in medical documentation can trigger DRG downgrades or denials from payers, causing severe revenue loss and intense administrative friction.
  • Administrative overhead: Compliance, managing audits, and tracking coding data require extensive infrastructure and divert resources away from direct patient care.

What is a DRG in simple terms?

A DRG (Diagnosis-Related Group) is a system that groups hospital patients with similar medical conditions together to decide how much insurance or Medicare will pay the hospital.

Instead of paying separately for every single pill, bandage, or test a patient receives during an Inpatient Prospective Payment System hospital stay, the insurance company pays a fixed, set amount based on that patient's specific DRG.

How a DRG Works

  • The Diagnosis: The hospital looks at the patient's main reason for being in the hospital, plus any other health conditions or extra procedures.
  • The Grouping: Code software sorts the case into a specific DRG category that matches the expected cost and care level.
  • The Payment: The hospital receives one flat fee for the whole stay.

Why the DRG System Exists

  • Cost Control: It stops hospitals from overcharging or running unnecessary tests because they do not get extra money for extra services.
  • Efficiency: It encourages hospitals to treat patients well and get them home safely without wasting time or supplies.
  • Financial Risk: If a patient's care costs less than the fixed DRG amount, the hospital keeps the difference as profit. If the care costs more, the hospital has to cover the loss.

What DRG does Medicare use?

Medicare uses the Medicare Severity Diagnosis-Related Group (MS-DRG) system to categorize inpatient hospital stays and determine fixed reimbursement rates under the Inpatient Prospective Payment System (IPPS).

How MS-DRGs Work

  • Fixed Payment: Medicare pays hospitals a set, predetermined amount for a patient's discharge based on their assigned MS-DRG, rather than paying separately for every individual service or day spent in the hospital.
  • Severity Tiers: MS-DRGs refine traditional DRGs by splitting categories into different tiers based on the presence of complications or comorbidities (CCs) and major complications or comorbidities (MCCs).
  • Assignment Factors: Grouping relies on patient data processed after discharge, including the principal diagnosis, secondary diagnoses, surgical procedures, age, sex, and discharge status.