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Short, plain-language guides to help patients and caregivers feel less lost when talking to providers and insurance companies.

Full insurance glossary

Every term grouped by topic: what you pay, coverage rules, plan mechanics, and policy terminology.

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Provider specialties

Who does what — primary care, internal medicine subspecialties, surgical specialties, and behavioral & rehab providers. When to see each, and how referrals usually flow.

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Quick glossary by category

What you pay

Premium

The monthly amount you (or your employer) pay just to have the plan.

Deductible

What you pay out of pocket before your plan starts sharing most costs.

Copay (Copayment)

A flat dollar amount you pay at the time of a visit or prescription.

Coinsurance

Your percentage share of a covered cost after the deductible is met.

Out-of-Pocket Maximum

The most you'll pay for covered, in-network care in a plan year.

Allowed Amount

The negotiated price your insurer recognizes for a service.

Balance Billing

When an out-of-network provider bills you for the gap above what your plan paid.

Explanation of Benefits (EOB)

The statement from your insurer showing what was billed, allowed, paid, and what you owe.

Good Faith Estimate

A written estimate of expected charges you can request before scheduled care.

Coverage rules & reviews

Medical Necessity

The insurer is reviewing whether the service is clinically appropriate for your situation.

Prior Authorization

Some services may need plan approval before they are performed.

Investigational

The insurer considers the service still under study for this use.

Conservative Treatment

Lower-risk care that insurers may want documented before a bigger procedure.

Cosmetic

The insurer may view the service as appearance-related rather than treating a medical condition.

Utilization Management

How insurers review whether services are clinically appropriate and efficient.

Step Therapy

Trying a preferred (often lower-cost) treatment first before a different one is approved.

Coverage Determination

A formal written decision from your insurer about whether a specific service will be covered.

Medical Policy / Clinical Policy

The insurer's published document defining exactly when a service is considered medically necessary.

Coverage Criteria

The specific clinical requirements a service must satisfy to meet medical necessity.

Letter of Medical Necessity

A physician letter explaining, in clinical terms, why a specific treatment is necessary for you.

How your plan works

In-Network vs Out-of-Network

Providers who contract with your plan cost less than those who don't.

Referral

A written order from your primary care provider to see a specialist.

Primary Care Provider (PCP)

The doctor who manages your overall care and coordinates referrals.

Non-Duplication of Benefits

When you have two plans, the secondary will not pay more than it would have if it were primary.

Coordination of Benefits (COB)

Rules that decide which of your plans pays first when you have more than one.

Network Tier

Some plans group in-network providers into preferred and standard tiers.

Plan Year vs Calendar Year

The 12-month window your deductible and OOP max reset on.

Embedded vs Aggregate Deductible

How a family plan's deductible applies to one member vs the whole family.

HMO (Health Maintenance Organization)

Lower premiums, but you must stay in-network and usually need a referral for specialists.

PPO (Preferred Provider Organization)

More flexibility to see any provider — in or out of network — without a referral.

EPO (Exclusive Provider Organization)

No referrals needed, but out-of-network care is not covered except in emergencies.

HSA (Health Savings Account)

A tax-advantaged savings account paired with a qualifying high-deductible health plan.

FSA (Flexible Spending Account)

A pre-tax spending account for eligible medical expenses — but usually 'use it or lose it'.

Policy & billing terminology

Formulary

The list of medications your plan covers, often with tiers.

Claim

A formal request for payment submitted to your insurer for a medical service.

CPT Code

A 5-digit code describing the specific procedure or service that was performed.

ICD Code

A code representing your diagnosis. Must support the procedure code for coverage.

NPI (National Provider Identifier)

A unique 10-digit ID for every licensed healthcare provider in the US.

Fully Insured Plan

Your insurer bears the financial risk — and that's what gives your state regulator authority.

Self-Funded Plan (ASO / ASC)

Your employer bears the risk, not the insurer — which changes who you'd complain to.

Medigap

A private policy that fills gaps in Original Medicare, standardized across insurers.

Medicare

Federal coverage for 65+ — appeals go through Medicare's own process, not your state.

Medicaid

State-run, income-based coverage — complaints go to your state's Medicaid agency, not the DOI.

ERISA

The federal law behind most employer plans — and why some plans fall outside state protection.

Appeals & denials

Adverse Determination

The formal legal term for an insurance denial.

Internal Appeal

Your first formal challenge to a denial — filed directly with the insurance company.

External Review

An independent, binding review of your denial by a neutral third party.

Independent Review Organization (IRO)

The neutral third party that conducts external reviews of insurance denials.

Expedited Appeal

A fast-tracked appeal for urgent clinical situations — decision within 72 hours.

Grievance

A formal complaint about a coverage decision, quality of care, or service problem.

Laws & patient rights

No Surprises Act

Federal protection against surprise out-of-network bills in emergencies and at in-network facilities.

ACA (Affordable Care Act)

The federal law that guaranteed appeal rights, essential benefits, and pre-existing condition protection.

COBRA

The right to continue employer coverage after leaving a job — at your own cost.

Open Enrollment

The annual window when you can enroll in or change your health plan.

Special Enrollment Period (SEP)

A window to change coverage outside open enrollment after a qualifying life event.