Reference Sources
Collection

Medicare reference sources

Know where to verify the answer. A curated guide to the official agencies, plan documents, directories, formularies, notices, and local resources used to confirm Medicare facts.

The Library explains what information means. These sources help confirm what is current and specific to you.

Choose what to confirm → See federal sources

This collection covers the official agencies, plan documents, directories, formularies, notices, and local resources used to confirm what is current and specific about a Medicare decision.

Start with what you need to confirm.

Pick the kind of fact you are checking, and go straight to the source that settles it.

Eligibility and enrollment

When you can sign up, and whether a penalty applies.

Federal sources →
Premiums and IRMAA

What Part B and Part D cost at your income.

Federal sources →
Plan benefits and costs

Copays, deductibles, and what a plan actually covers.

Plan documents →
Prescription coverage

Whether a drug is covered, its tier, and its rules.

Plan documents →
Doctor or hospital in network

Whether a provider participates for the year.

Plan documents →
A denial or a bill

How to read a notice and start an appeal.

State help →
State rights and protections

Medigap rules and windows that vary by state.

State help →
Free local counseling

Unbiased one-on-one help near you.

State help →

Federal sources.

The official record for eligibility, enrollment, premiums, and program rules.

Medicare.gov
Centers for Medicare & Medicaid Services

The official consumer site for comparing plans, checking coverage, and finding providers.

Use it to confirm
  • Plan and drug plan comparisons
  • Whether a provider or supplier participates
  • What Original Medicare covers

When it is not enough: Plan-specific details can lag the plan's own documents. Confirm the exact cost with the plan.

Visit Medicare.gov ↗

Links open official government sites in a new tab. The Clearing is not affiliated with any government agency.

CMS.gov
Centers for Medicare & Medicaid Services

The agency that runs Medicare. The source for program rules, manuals, and official guidance.

Use it to confirm
  • Program rules and regulations
  • Annual figures and deductibles
  • Official policy and guidance

When it is not enough: Written for administration, not consumers. Use it to confirm a rule, not to choose a plan.

Visit CMS.gov ↗

Links open official government sites in a new tab. The Clearing is not affiliated with any government agency.

Social Security
Social Security Administration

Handles Medicare enrollment, Part B premiums, and income-related premium adjustments (IRMAA).

Use it to confirm
  • Enrollment and effective dates
  • Your Part B premium and any IRMAA
  • Requesting an IRMAA reconsideration

When it is not enough: Covers enrollment and premiums, not plan benefits or coverage decisions.

Visit SSA.gov ↗

Links open official government sites in a new tab. The Clearing is not affiliated with any government agency.

Plan documents and notices.

Your plan is the controlling source for its own benefits, costs, and network. These are the documents where the details actually live.

Evidence of Coverage
EOC

The full legal description of what your plan covers, what it costs, and its rules. The controlling document for benefits.

When you get it: Annually, and on request
Verify against: The plan directly for anything time-sensitive
Summary of Benefits
SB

A shorter overview of major benefits and costs, useful for a first comparison between plans.

When you get it: During enrollment
Verify against: The EOC for exact terms and limits
Annual Notice of Changes
ANOC

What is changing in your current plan for next year: costs, benefits, and formulary changes.

When you get it: Each fall, before AEP
Verify against: Next year's SB and formulary
Formulary (drug list)

The list of drugs the plan covers, their tiers, and restrictions such as prior authorization or step therapy.

When you get it: Annually; can change in-year
Verify against: The plan's current online formulary
Provider directory

Which doctors, hospitals, and pharmacies are in the plan's network for the year.

When you get it: Ongoing; updated often
Verify against: The provider's office and the plan
Denial or coverage notice

The plan's written explanation of a denied service or drug, and your appeal rights and deadlines.

When you get it: When a claim is denied
Verify against: The appeal deadline on the notice
Explanation of Benefits
EOB

A monthly summary of claims processed. Not a bill, but the record to check for errors.

When you get it: Monthly, when you use care
Verify against: Provider bills and the plan

State and local help.

Free, unbiased counseling and the offices that handle state-specific rights and protections.

SHIP
Free

State Health Insurance Assistance Programs offer free, unbiased one-on-one Medicare counseling.

Use when: You want neutral help comparing or appealing
State insurance department

Regulates insurance in your state and handles complaints about plans and agents.

Use when: A plan or agent has treated you unfairly
State Medicaid office

Determines Medicaid eligibility and administers programs that help with Medicare costs.

Use when: You may qualify for help with premiums or costs
Area Agency on Aging
Free

Local hub for services for older adults, including benefits counseling and referrals.

Use when: You need local support beyond Medicare
Medicare Savings Programs

State-run programs that help pay Part B premiums and other costs for those who qualify.

Use when: Premiums are a strain and income is limited
State Medigap protections

Some states add enrollment windows or guaranteed-issue rights beyond the federal minimum.

Use when: You are buying or switching a Medigap policy
Find SHIP in your state →

One source is not always the whole answer.

A single source can be right in general and wrong for your plan, your state, or this year. Confirming a Medicare fact usually means checking it in the source that actually controls it, then writing down what you found.

1
Find the controlling source

Identify which source actually decides this fact — the plan, the agency, or your state.

2
Confirm the exact detail

Check the specific number, date, or rule as it applies to you, not the general version.

3
Record the date and answer

Write down what you found and when. Rules and prices change through the year.

4
Note what is still uncertain

Flag anything a source could not settle, and who you still need to ask.

Clearing guides for using these sources.

Step-by-step help for turning an official source into a confirmed answer.

How to check whether your doctors are covered How to read a Part D formulary How to compare two plan documents How to document a phone call with a plan How to check an enrollment right or window How to find the source that controls an answer
A note on official sources

Official sources can still be general, out of date, incomplete, or hard to apply to one person’s situation. Treat time-sensitive and plan-specific facts as things to confirm directly, close to when you act, and keep a record of the date and the answer. The Clearing does not sell insurance, recommend plans, or provide medical, legal, or financial advice.

Medicare decision tools

Found the source. Now apply it.

Reference sources confirm the facts. Decision Tools help you use them on your own situation.

Explore Decision Tools → Start with the Self-Audit →

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