Glossary & Acronyms

The A–Z of US healthcare administration. Every acronym a payer, provider, or vendor will throw at you, decoded in one line. Terms with their own page are wikilinked so you can follow them for the full picture.

A

• ACA — Affordable Care Act — the 2010 law that created the insurance marketplaces, banned pre-existing-condition exclusions, and set the MLR rules. See The Affordable Care Act (ACA).
• ACO — Accountable Care Organization — a group of providers held jointly accountable for the cost and quality of a defined patient population. See Accountable Care Organizations (ACOs).
• ADL — Activities of Daily Living — basic self-care tasks (bathing, dressing, eating); used to assess long-term care need.
• AKS — Anti-Kickback Statute — federal criminal law barring payment for referrals of items or services paid by federal health programs. See Stark Law & the Anti-Kickback Statute.
• APC — Ambulatory Payment Classification — the unit Medicare uses to pay for hospital outpatient services. See DRGs & Prospective Payment Systems.
• APM — Alternative Payment Model — any payment arrangement that moves away from pure fee-for-service toward value or risk.
• ASO — Administrative Services Only — an arrangement where a carrier processes claims for a self-funded employer but bears no insurance risk. See Self-Funded Plans & ASO.
• ASP — Average Sales Price — the benchmark Medicare uses to reimburse most Part B drugs.

B

• BPCI — Bundled Payments for Care Improvement — a CMS program paying a single fixed amount for an episode of care. See Bundled & Episode-Based Payments.

C

• CAQH — Council for Affordable Quality Healthcare — a non-profit running shared provider-data and credentialing utilities used across networks.
• CDI — Clinical Documentation Integrity (or Improvement) — work to ensure the medical record fully and accurately supports coding and billing. See Clinical Documentation Integrity (CDI).
• CMS — Centers for Medicare & Medicaid Services — the federal agency that runs Medicare, Medicaid, and the marketplaces; the single biggest rule-maker in US healthcare. See CMS (Centers for Medicare & Medicaid Services).
• CMS-0057-F — the Interoperability and Prior Authorization Final Rule: standard PA decisions in 7 calendar days, expedited in 72 hours (effective Jan 1 2026); production FHIR APIs by Jan 1 2027.
• COB — Coordination of Benefits — the rules deciding which plan pays first when a member has two. See Coordination of Benefits & Subrogation.
• CPT — Current Procedural Terminology — the AMA's code set for procedures and services; the language of physician billing. See Medical Coding Systems.
• CRD — Coverage Requirements Discovery — a Da Vinci FHIR workflow that tells a provider, at the point of order, whether prior auth is needed.

D

• DME — Durable Medical Equipment — reusable medical gear (wheelchairs, CPAP, oxygen) prescribed for home use. See Durable Medical Equipment (DME) Review.
• DOI — Department of Insurance — the state regulator licensing insurers and handling consumer complaints. See State Regulation & Departments of Insurance.
• DRG — Diagnosis-Related Group — the bucket that sets a fixed inpatient payment per admission regardless of length of stay. See DRGs & Prospective Payment Systems.
• D-SNP — Dual-Eligible Special Needs Plan — a Medicare Advantage plan built for people on both Medicare and Medicaid. See Dual Eligibles & D-SNPs.
• DTR — Documentation Templates and Rules — a Da Vinci FHIR app that gathers the documentation a payer needs for a PA, pre-filled from the EHR.

E

• EDI — Electronic Data Interchange — the standardized electronic exchange of business documents (claims, eligibility, remittances) between trading partners. See EDI & X12 Transaction Standards.
• EHB — Essential Health Benefits — the ten benefit categories ACA plans must cover (e.g. emergency, maternity, mental health).
• EHR — Electronic Health Record — the digital chart that runs a provider's clinical and billing operations. See EHRs & the Provider Tech Stack.
• EOB — Explanation of Benefits — the statement a plan sends a member after a claim, showing what was billed, allowed, and owed. See Cost Sharing.
• EPO — Exclusive Provider Organization — a plan that covers only in-network care (except emergencies) but skips the PCP-referral requirement.
• ERISA — Employee Retirement Income Security Act — the 1974 law governing employer-sponsored plans; it largely pre-empts state regulation of self-funded plans. See ERISA & Self-Funded Plans.

F

• FFS — Fee-for-Service — paying providers per item of service; the default model risk-based care tries to replace. See Fee-for-Service vs Value-Based Care.
• FHIR — Fast Healthcare Interoperability Resources — the modern HL7 API standard for exchanging health data as discrete, web-friendly resources. See HL7, FHIR & USCDI.
• FPL — Federal Poverty Level — the income benchmark used to set Medicaid and ACA subsidy eligibility.
• FWA — Fraud, Waste and Abuse — the umbrella for improper billing, from outright fraud to careless waste; policed by the SIU. See Fraud, Waste & Abuse (FWA) & the SIU.

G

• Gold-Carding — exempting reliably-compliant providers from prior auth for specified services. See Gold-Carding & Auto-Approval.
• Grievance — a formal complaint about a plan's service or operations, distinct from an appeal of a coverage decision. See Appeals & Grievances.

H

• HCC — Hierarchical Condition Category — the diagnosis groupings that drive risk-adjusted payment in Medicare Advantage and ACA plans. See Risk Adjustment & HCC Coding.
• HCPCS — Healthcare Common Procedure Coding System — Medicare's code set; Level I is CPT, Level II covers supplies, drugs, and DME. See Medical Coding Systems.
• HDHP — High-Deductible Health Plan — a plan with a high deductible, usually paired with an HSA. See Plan Types (HMO, PPO, EPO, POS, HDHP).
• HEDIS — Healthcare Effectiveness Data and Information Set — NCQA's standardized quality-measure set used to score plans. See Quality Measurement (HEDIS, Stars, MIPS).
• HHA — Home Health Agency — an organization delivering skilled nursing and therapy in the home. See Post-Acute & Long-Term Care.
• HIE — Health Information Exchange — the infrastructure (and the act) of sharing clinical data across organizations. See TEFCA & Health Information Exchange.
• HIPAA — Health Insurance Portability and Accountability Act — the 1996 law setting privacy and security rules for PHI and mandating standard EDI transactions. See HIPAA.
• HITECH — Health Information Technology for Economic and Clinical Health Act — the 2009 law that funded EHR adoption and strengthened HIPAA enforcement.
• HL7 — Health Level Seven — the standards body behind clinical-data formats, including v2 messaging and FHIR. See HL7, FHIR & USCDI.
• HMO — Health Maintenance Organization — a plan that requires in-network care and usually a PCP referral to see specialists. See Plan Types (HMO, PPO, EPO, POS, HDHP).
• HSA — Health Savings Account — a tax-advantaged account paired with an HDHP to pay out-of-pocket costs.

I

• ICD-10 — International Classification of Diseases, 10th Revision — the diagnosis (and inpatient procedure) code set; the vocabulary of "what's wrong." See Medical Coding Systems.
• IDR — Independent Dispute Resolution — the No Surprises Act's baseball-style arbitration for out-of-network payment disputes. See The No Surprises Act.
• IPA — Independent Practice Association — a legal entity of independent physicians who contract collectively with payers, often taking risk. See Physician Groups, IPAs & Medical Groups.
• IRO — Independent Review Organization — an external body that adjudicates appeals at the external-review stage. See Appeals & Grievances.
• IRR — Inter-Rater Reliability — the consistency with which different reviewers reach the same UM decision on the same case. See Inter-Rater Reliability (IRR).

L

• LCD — Local Coverage Determination — a coverage policy set by a regional Medicare contractor (MAC). See Local & National Coverage Determinations (LCD & NCD).
• LOINC — Logical Observation Identifiers Names and Codes — the standard code set for lab tests and clinical observations. See Medical Coding Systems.
• LOS — Length of Stay — the number of days a patient is hospitalized; the central variable in concurrent review and DRG economics.
• LTACH — Long-Term Acute Care Hospital — a facility for medically complex patients needing extended hospital-level care. See Post-Acute & Long-Term Care.

M

• MA — Medicare Advantage — privately-run Medicare (Part C), paid a capitated, risk-adjusted rate by CMS. See Medicare Advantage.
• MAC — Medicare Administrative Contractor — the private companies CMS hires to process Medicare claims and issue LCDs in each region.
• MCG — a widely-used set of evidence-based clinical criteria for medical-necessity decisions (formerly Milliman Care Guidelines). See Clinical Criteria (MCG & InterQual).
• MCO — Managed Care Organization — a plan that integrates financing and care delivery to manage cost and utilization; the dominant form of managed Medicaid. See Payers (Health Plans).
• MHPAEA — Mental Health Parity and Addiction Equity Act — the 2008 law requiring behavioral-health benefits to be no more restrictive than medical/surgical ones. See Mental Health Parity (MHPAEA).
• MIPS — Merit-based Incentive Payment System — Medicare's pay-for-performance track for clinicians. See Quality Measurement (HEDIS, Stars, MIPS).
• MLR — Medical Loss Ratio — the share of premium spent on care; ACA floors are 80% (individual/small group) and 85% (large group), with rebates owed below. See Medical Loss Ratio (MLR).
• MOOP — Maximum Out-of-Pocket — the annual cap on a member's cost sharing, after which the plan pays 100%. See Cost Sharing.
• MSO — Management Services Organization — an entity providing administrative infrastructure (billing, contracting, Utilization Management) to medical groups. See Physician Groups, IPAs & Medical Groups.

N

• NCD — National Coverage Determination — a nationwide Medicare coverage policy issued by CMS. See Local & National Coverage Determinations (LCD & NCD).
• NCPDP — National Council for Prescription Drug Programs — the standards body for pharmacy-claim transactions. See Pharmacy Benefit Managers (PBMs).
• NCQA — National Committee for Quality Assurance — the leading accreditor of health plans; owner of HEDIS. See Accreditation (NCQA & URAC).
• NDC — National Drug Code — the unique identifier for a specific drug product, package, and manufacturer. See Medical Coding Systems.
• NPI — National Provider Identifier — the unique 10-digit ID for every US provider and organization, used on every claim.
• NQTL — Non-Quantitative Treatment Limitation — a non-numeric coverage limit (e.g. prior auth, step therapy) scrutinized under parity rules. See Behavioral Health Management & Parity.
• NSA — No Surprises Act — the 2022 law banning balance billing for most out-of-network emergency and ancillary care. See The No Surprises Act.

O

• OON — Out-of-Network — care from a provider with no contract with the member's plan, usually at higher cost. See Provider Networks.
• OOP — Out-of-Pocket — what the member pays directly (deductible, copay, coinsurance). See Cost Sharing.
• OPPS — Outpatient Prospective Payment System — Medicare's payment system for hospital outpatient services, built on APCs. See DRGs & Prospective Payment Systems.

P

• PA — Prior Authorization — a payer's requirement to approve a service before it is delivered or paid. See Prior Authorization.
• PAS — Prior Authorization Support — the Da Vinci FHIR workflow that submits a PA request electronically and returns a decision.
• PBM — Pharmacy Benefit Manager — the middleman administering the drug benefit: formularies, rebates, and pharmacy networks. See Pharmacy Benefit Managers (PBMs).
• PCP — Primary Care Provider — the member's first-line doctor and, in HMOs, the gatekeeper to specialists. See Providers & Health Systems.
• PHI — Protected Health Information — individually identifiable health data covered by HIPAA. See HIPAA.
• PHE — Public Health Emergency — a federally-declared status that can temporarily waive program rules (e.g. telehealth, Medicaid eligibility).
• PMPM — Per Member Per Month — the standard unit of capitated payment and plan-cost measurement. See Capitation, Full-Risk & Delegated Risk.
• POS — Point of Service (plan) — a hybrid plan letting members go out-of-network at higher cost. Also "place of service" code on a claim. See Plan Types (HMO, PPO, EPO, POS, HDHP).
• PPO — Preferred Provider Organization — a plan with a network but no referral requirement and out-of-network coverage at higher cost. See Plan Types (HMO, PPO, EPO, POS, HDHP).
• PPS — Prospective Payment System — any system paying a predetermined amount per unit of care (per DRG, per APC). See DRGs & Prospective Payment Systems.

Q

• QHIN — Qualified Health Information Network — a designated network forming the backbone of TEFCA nationwide exchange. See TEFCA & Health Information Exchange.
• QHP — Qualified Health Plan — a plan certified to sell on the ACA marketplace. See ACA Marketplace Plans.
• QPA — Qualifying Payment Amount — the median in-network rate used as the benchmark in No Surprises Act disputes. See The No Surprises Act.

R

• RADV — Risk Adjustment Data Validation — CMS audits verifying that MA diagnoses (and the resulting RAF) are backed by the medical record. See Risk Adjustment & HCC Coding.
• RAF — Risk Adjustment Factor — the per-member score, built from HCCs and demographics, that scales a plan's payment. See Risk Adjustment & HCC Coding.
• RBM — Radiology Benefit Manager — a specialty manager handling imaging authorizations. See Specialty Benefit Managers.
• RBRVS — Resource-Based Relative Value Scale — the framework, built on RVUs, that sets Medicare physician fees. See Fee Schedules & Allowed Amounts.
• RCM — Revenue Cycle Management — the provider-side process of turning care delivered into cash collected. See Revenue Cycle Management (RCM).
• RFI — Request for Information — a payer's request for additional clinical documentation to complete a PA or claim review. See Information Requests & RFI Templates.
• RPM — Remote Patient Monitoring — collecting patient data from devices at home for clinical management and billing. See Remote Monitoring & Digital Health Programs.
• RVU — Relative Value Unit — the unit measuring the resources behind a service; multiplied by a conversion factor to set the fee. See Fee Schedules & Allowed Amounts.

S

• SaaS — Software as a Service — cloud-delivered, subscription software; the default delivery model for modern health-IT. See Building & Selling Healthtech (Go-to-Market).
• SBC — Summary of Benefits and Coverage — the standardized plain-language plan summary the ACA requires plans to give members. See Benefit Design & the SBC.
• SDOH — Social Determinants of Health — the non-clinical conditions (housing, food, transport) that shape health outcomes. See Care Gaps & SDOH.
• SIU — Special Investigations Unit — the payer team that investigates fraud, waste, and abuse. See Fraud, Waste & Abuse (FWA) & the SIU.
• SMART on FHIR — a standard for launching third-party apps securely inside an EHR using FHIR. See SMART on FHIR & EHR Apps.
• SNF — Skilled Nursing Facility — a post-acute facility providing short-term skilled nursing and rehab after a hospital stay. See Post-Acute Care Review.
• SNP — Special Needs Plan — a Medicare Advantage plan tailored to a specific population (dual-eligibles, chronic conditions, institutionalized). See Dual Eligibles & D-SNPs.
• SUD — Substance Use Disorder — addiction-related conditions; a parity-protected benefit category. See Behavioral Health Review.

T

• TAT — Turnaround Time — the regulated clock for making and communicating a PA or appeal decision. See Turnaround Time & Regulatory Clocks.
• TEFCA — Trusted Exchange Framework and Common Agreement — the national framework, run via QHINs, for nationwide health-data exchange. See TEFCA & Health Information Exchange.
• TPA — Third Party Administrator — a firm that administers claims and benefits for self-funded plans without bearing risk. See Third Party Administrators (TPAs).

U

• UM — Utilization Management — the payer function controlling whether, where, and how much care is authorized and paid. See Utilization Management.
• UR — Utilization Review — the clinical review of a service's medical necessity (prospective, concurrent, or retrospective). See Utilization Review.
• URAC — an accreditor of health-plan and Utilization Management operations (originally the Utilization Review Accreditation Commission). See Accreditation (NCQA & URAC).
• USCDI — United States Core Data for Interoperability — the standard baseline set of data classes payers and providers must exchange. See HL7, FHIR & USCDI.

V

• VBC — Value-Based Care — paying for outcomes and total cost rather than volume of services. See Fee-for-Service vs Value-Based Care.
• VBID — Value-Based Insurance Design — benefit design that lowers cost sharing for high-value services to steer behavior.

W

• WAC — Wholesale Acquisition Cost — a drug's list price to wholesalers, a reference point in drug pricing. See Formularies, Rebates & the Drug Supply Chain.

X

• X12 — the ANSI committee and its EDI standards behind core HIPAA transactions (the 837 claim, 270/271 eligibility, 278 prior auth, 835 remittance). See EDI & X12 Transaction Standards.

Related

• Home
• How to Use This Map
• The 90-Second Mental Model
• The Stakeholders
• Prior Authorization
• Utilization Management
• Medical Coding Systems
• EDI & X12 Transaction Standards
• Risk Adjustment & HCC Coding
• The CMS Interoperability & Prior Authorization Final Rule (CMS-0057-F)
• Regulation & Policy
• The Health-IT Vendor Map

Sources

• CMS — Interoperability and Prior Authorization Final Rule (CMS-0057-F) Fact Sheet
• KFF — Explaining Health Care Reform: Medical Loss Ratio (MLR)
• CMS — Medicare Advantage Risk Adjustment Data Validation Program
• ONC/ASTP — Trusted Exchange Framework and Common Agreement (TEFCA)