The CMS MS-DRG Grouper is the authoritative software developed and maintained by the Centers for Medicare & Medicaid Services (CMS) for use in the Medicare Inpatient Prospective Payment System (IPPS). Its primary function is to classify hospital inpatient discharges into one of approximately 775 MS-DRGs based on a complex algorithm. This classification determines the fixed payment rate a hospital receives for treating Medicare patients.
Key Functions and Capabilities:
- DRG Assignment: Assigns a single MS-DRG based on the patient's principal diagnosis, up to 24 secondary diagnoses, up to 25 procedures, age, sex, and discharge status.
- Severity Adjustment: Incorporates the logic for Complications/Comorbidities (CCs) and Major Complications/Comorbidities (MCCs) to adjust the payment weight based on the severity of the patient's condition.
- Medicare Code Editor (MCE): Includes the MCE logic, which detects and reports errors in the ICD-10-CM/PCS coding and claims data to ensure coding compliance.
- Output Data: Returns the assigned MS-DRG, Major Diagnostic Category (MDC), Relative Weight (used to calculate payment), and validation/edit errors.
- Updates: The software and its logic are updated at least annually (October 1st) and sometimes semi-annually (April 1st) to reflect changes in ICD-10 codes and IPPS rules.
Target Users and Use Cases: This software is primarily used by hospitals, Medicare Administrative Contractors (MACs), and third-party software vendors. It is not a user-friendly application but a programmatic utility for integration into larger systems.
- Claims Processing: Used by hospitals and MACs to accurately group claims for Medicare reimbursement.
- Software Development: The Java source code and binaries are used by Electronic Health Record (EHR) and billing software vendors (Integrations) to build compliant grouping logic into their commercial products.
- Compliance & Auditing: Used for internal compliance auditing and claim review to validate the assigned DRG and ensure proper documentation.