MS-DRG
Medicare Severity Diagnosis Related Group
Medicare Severity Diagnosis Related Groups — the classification system used to pay inpatient hospital admissions under Medicare's prospective payment system.
1 min read · Last reviewed May 23, 2026
At a glance
- Category
- Billing
- Acronym for
- Medicare Severity Diagnosis Related Group
- Primary sources
- 2
- Workspace handoff
- ask d3 →
Where this comes up
This shows up in revenue-cycle work — claim scrubbing, charge entry, posting, A/R follow-up, and month-end close. Billers and practice managers hit this term when reconciling a payment, working a denial queue, or auditing why a claim aged past 60 days.
Full definition
What it is in practice
CMS groups inpatient stays into MS-DRGs based on principal diagnosis, secondary diagnoses, procedures, age, sex, and discharge status. Each MS-DRG has a weight that drives payment.
How it shows up in your practice
Hospital coders manage MS-DRG assignment; physician practices interact when documentation supports a higher-severity DRG (CC/MCC capture).
Sources
- CMS — Acute Inpatient PPShttps://www.cms.gov/medicare/payment/prospective-payment-systems/acute-inpatient-pps
- CMS — MS-DRG Classifications and Softwarehttps://www.cms.gov/medicare/payment/prospective-payment-systems/acute-inpatient-pps/ms-drg-classifications-and-software
Look up MS-DRG specifics in Ask D3
Open ask d3 →Related terms
- BillingInpatient Hospital BillingFacility billing for hospitalized patients, classified using the MS-DRG system under the Acute Inpatient Prospective Payment System.
- CodingICD-10-PCSThe Procedural Coding System used in the United States to report inpatient hospital procedures.
- BillingTwo-Midnight RuleMedicare policy that generally treats a stay spanning two midnights as appropriate for inpatient admission.
D3rx is a healthcare-billing and compliance research aid maintained by D3rx Inc. Articles are drafted by an LLM (Anthropic Claude) against primary HHS, OCR, CMS, eCFR, NIST, and state-regulator publications, and reviewed for restraint and source fidelity by the D3rx team.
Reviewer status: a named credentialed reviewer (CHC, CHPC, or healthcare attorney) is being engaged. Until that engagement is finalized, this page does not claim credentialed review.
Related across the archive
- GlossaryInpatient Hospital BillingFacility billing for hospitalized patients, classified using the MS-DRG system under the Acute Inpatient Prospective Payment System.
- GlossaryICD-10-PCSThe Procedural Coding System used in the United States to report inpatient hospital procedures.
- GlossaryTwo-Midnight RuleMedicare policy that generally treats a stay spanning two midnights as appropriate for inpatient admission.
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This glossary entry is a research aid for billing and compliance staff. It does not provide legal, medical, or financial advice and does not replace counsel. References cited link to primary sources at HHS, OCR, CMS, eCFR, NIST, and the relevant payer or industry body.