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MEDICARE BASICS: COMMONLY USED ACRONYMS Target Audience: Medicare Fee-For-Service Providers

If you interact with Medicare, you probably come across acronyms on a regular basis. It can be difficult to keep track of them all!

This resource lists Medicare-related acronyms. While the list is not all-inclusive, it contains those acronyms you may encounter in Medicare and Medicare Learning Network® (MLN) products.

What Is an Acronym?
An acronym is a word formed from the initial letters or parts of a name or title.

Want more information about Medicare? Watch this 5-minute Centers for Medicare & Medicaid Services (CMS) What Is Medicare? video for a high-level overview of the Medicare Program, including basic information about Medicare’s various parts and who they cover.


  • ABD: Aged, Blind, and Disabled

  • ACH: Automated Clearing House

  • ACP: Advance Care Planning

  • AHRQ: Agency for Healthcare Research and Quality

  • ALJ: Administrative Law Judge

  • ALOS: Average Length of Stay

  • ANSI: American National Standards Institute

  • AO: Accreditation Organization

  • APA: American Pharmaceutical Association

  • APA: American Psychiatric Association

  • ASC: Accredited Standards Committee

  • AWP: Average Wholesale Price


  • BBA: Balanced Budget Act of 1997

  • BHO: Behavioral Health Organization


  • CAL: Coding Analysis for Labs

  • CARC: Claims Adjustment Reason Code

  • CAT: Computerized Axial Tomography

  • CCN: Claim Control Number

  • CE: Continuing Education

  • CEUs: Continuing Education Units

  • CF: Conversion Factor

  • CFC: Conditions for Coverage

  • CFR: Code of Federal Regulations

  • CME: Continuing Medical Education

  • CMN: Certificate of Medical Necessity

  • CMP: Civil Monetary Penalty

  • CMSCE: Centers for Medicare & Medicaid Services Continuing Education Program

  • COBRA: Consolidated Omnibus Budget Reconciliation Act

  • COP: Conditions of Participation

  • COPD: Chronic Obstructive Pulmonary Disease

  • CPAP: Continuous Positive Airway Pressure

  • CPI: Consumer Price Index

  • CR: Change Request

  • CWF: Common Working File


  • DBA: Doing Business As

  • DCN: Document Control Number

  • DDE: Direct Data Entry

  • DEA: Drug Enforcement Administration

  • DOB: Date of Birth

  • DOD: Date of Death

  • DOE: Date of Entitlement

  • DOJ: U.S. Department of Justice

  • DOS: Date of Service

  • DUA: Data Use Agreement

  • DUR: Drug Utilization Review

  • DV: Data Validation

  • DX: Diagnosis


  • ED: Emergency Department

  • EDI: Electronic Data Interchange

  • EFT: Electronic Funds Transfer

  • EGHP: Employer Group Health Plan

  • EIN: Employer Identification Number

  • EMT: Emergency Medical Technician

  • EOB: Explanation of Benefits

  • EOC: Episode of Care

  • EP: Eligible Professional

  • ER: Emergency Room

  • eRx: Electronic Prescribing


  • FAQ: Frequently Asked Question

  • FAR: Federal Acquisition Regulations

  • FCBC: Fingerprint-Based Criminal Background Check

  • FID: Fraud Investigation Database

  • FISS: Fiscal Intermediary Standard (or Shared) System

  • FL: Form/Field Location

  • FOIA: Freedom of Information Act

  • FPS: Fraud Prevention System

  • FWA: Fraud, Waste, and Abuse

  • FY: Fiscal Year


  • GHP: Group Health Plan

  • GPCI: Geographic Practice Cost Index


  • HETS: Health Insurance Portability and Accountability Act (HIPAA) Eligibility Transaction System

  • HH: Home Health

  • HIPAA: Health Insurance Portability and Accountability Act of 1996

  • HIPPS: Health Insurance Prospective Payment System

  • HIV: Human Immunodeficiency Virus

  • HMO: Health Maintenance Organization

  • HSA: Health Savings Account

  • HUB Zone: Historically Underutilized Business Zone


  • I&A: Identity & Access Management System

  • IACS: Individuals Authorized to Access CMS Computer Services

  • IADL: Instrumental Activities of Daily Living

  • IBT: Intensive Behavioral Therapy

  • IDE: Investigational Device Exemption

  • IDTF: Independent Diagnostic Testing Facility

  • IHS: Indian Health Services

  • IME: Indirect Medical Education


  • For a list of Medicare-related acronyms that start with the letter J, visit the CMS Acronyms webpage.


  • For a list of Medicare-related acronyms that start with the letter K, visit the CMS Acronyms webpage.


  • LIDOS: Line Item Date of Service

  • LMS: Learning Managment System

  • LOC: Level of Care

  • LOS: Length of Stay

  • LPN: Licensed Practical Nurse


  • MACRA: Medicare Access and CHIP Reauthorization Act of 2015

  • MAO: Medicare Advantage Organization

  • MCE: Medicare Code Editor

  • MCP: Managed Care Plan

  • MDH: Medicare Dependent Hospital

  • MEDIGAP: Medicare Gap (Medicare supplement insurance)

  • MEDPAC: Medicare Payment Advisory Commission

  • MIPPA: Medicare Improvements for Patients and Providers Act

  • MIPS: Merit-Based Incentive Payment System

  • MLN LMS: Medicare Learning Network® Learning Management System

  • MMA: Medicare Modernization Act

  • MOC: Maintenance of Certification

  • MOON: Medicare Outpatient Observation Notice

  • MQSA: Mammography Quality Standards Act

  • MSA: Medical Savings Account

  • MSN: Medicare Summary Notice


  • NABP: National Association of Boards of Pharmacy

  • NP: Nurse Practitioner

  • NQF: National Quality Forum

  • NUCC: National Uniform Claim Committee


  • OIG: Office of Inspector General (also see HHS OIG)

  • OPT: Outpatient Physical Therapy

  • OTAF: Obligated to Accept as Payment in Full


  • PA: Physician Assistant

  • PACE: Program of All-Inclusive Care for the Elderly

  • PAP: Positive Airway Pressure

  • PFFS: Private Fee-For-Service

  • PHI: Protected Health Information

  • PI: Program Integrity

  • PIN: Personal/Provider Identification Number

  • POC: Plan of Care

  • POS: Place of Service

  • POV: Power Operated Vehicle

  • PPO: Preferred Provider Organization

  • PPPS: Personalized Prevention Plan Services

  • PT: Physical Therapy

  • PTAN: Provider Transaction Access Number

  • PWC: Power Wheelchair



  • RA: Remittance Advice

  • RAP: Request for Anticipated Payment

  • RARC: Remittance Advice Remark Code

  • RN: Registered Nurse

  • RNHCI: Religious Nonmedical Health Care Institution

  • RRB: Railroad Retirement Board

  • RTP: Return to Provider

  • RVU: Relative Value Unit


  • SA: State Survey Agency

  • SAMHSA: Substance Abuse and Mental Health Services Administration

  • SCH: Sole Community Hospital

  • SCHIP: State Children’s Health Insurance Program

  • SLP: Speech Language Pathologist/Pathology

  • SMAC: Specialty Medicare Administrative Contractor

  • SME: Subject Matter Expert

  • SNF VBP: Skilled Nursing Facility Value-Based Purchasing Program

  • SNP: Special Needs Plan

  • SOM: State Operations Manual

  • SSA: Social Security Act (also called “the Act”)

  • SSN: Social Security Number



  • UPIC: Unified Program Integrity Contractor


  • For a list of Medicare-related acronyms that start with the letter V, visit the CMS Acronyms webpage.


  • WA: Working Aged

  • WBT: Web-Based Training

  • WEDI: Workgroup for Electronic Data Interchange


  • For a list of Medicare-related acronyms that start with the letter X, visit the CMS Acronyms webpage.


  • YTD: Year to Date



For a complete list of Medicare-related acronyms, visit the CMS Acronyms webpage.

For a glossary of terms, visit the CMS Glossary webpage.

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