Glossary
Inpatient vs Outpatient
The billing distinction between formal hospital admission (Part A) and outpatient hospital services (Part B), with major cost and coverage consequences.
Also known as: hospital status, admission status
Quick answer
Inpatient means a physician has formally admitted you to the hospital, triggering Part A coverage and the Part A deductible. Outpatient covers ER visits, observation, same-day surgery, and most diagnostics under Part B.
Why it matters
Cost-sharing, SNF eligibility, and even drug coverage all hinge on this distinction.
When you'll encounter it
Any hospital visit.
Impact on Medicare
Inpatient → Part A. Outpatient → Part B.
Impact on TRICARE For Life
TFL pays secondary in either case but cannot convert one to the other.
Common misconceptions
- "Length of stay determines status." — Physician orders and billing determine status.
What should I do?
- 1Always ask: 'Has the doctor written an inpatient admission order?'
- 2Get a copy of any MOON notice for observation stays.
Continue learning
— suggested by the knowledge graph- Frequently asked questions about Medicare and TRICARE For LifeA quick-reference summary of the questions retired service members and spouses ask most often — with citations to the official source.
- Common mistakes retired military make at 65 — and how to avoid themThe most expensive errors retired service members and spouses make during the Medicare and TFL transition, and the simple fixes for each.
- How Medicare and TRICARE For Life claims are paidThe mechanics of the Medicare-to-TFL crossover system — what providers do, what WPS does, and what to do if a claim gets stuck.
- AppealA formal request to review and reverse a denial, partial payment, or coverage decision by Medicare, a Medicare plan, TRICARE/TFL, VA, or a drug plan.
- Balance BillingThe practice of a provider billing you for the difference between their charge and what insurance approved.
- Billing ErrorsMistakes — accidental or intentional — on Medicare or TFL claims, ranging from duplicate charges to outright fraud.
- ClaimA formal request to an insurer for payment of a covered service.
- Claim AppealThe formal process for asking Medicare or TFL to reconsider a denied or underpaid claim.
- COBRA After 65COBRA is not creditable coverage for Part B — using it past 65 instead of enrolling in Medicare causes lifetime late penalties.
- Continued Health Care Benefit Program (CHCBP)A 18- to 36-month temporary TRICARE-like coverage option for those who lose TRICARE eligibility — functionally the military version of COBRA.
- Who pays first, Medicare or TRICARE For Life?Medicare pays first for any service it covers. TFL pays second. The claim usually crosses over automatically — you should never pay out of pocket up front.
- Does TRICARE For Life work overseas?Yes. Overseas, TFL acts as your primary payer because Medicare generally doesn't pay outside the U.S. You'll usually pay the provider up front and file a paper claim with TFL overseas.
- What are the biggest mistakes retired military make at 65?Declining Part B, missing the IEP, ignoring DEERS, enrolling in Part D unnecessarily, and assuming MTF access continues. Each can cost thousands or end TFL.
- I have other insurance besides Medicare and TFL. Who pays first?Order varies. Active-employment group insurance pays before Medicare; retiree coverage like FEHB pays after Medicare and usually before TFL. TFL is almost always last.
- A doctor is balance-billing me. Is that legal?Medicare-participating providers cannot balance bill. Non-participating providers can charge up to the limiting charge. Opt-out providers can bill anything. Identify the type before paying.
Related glossary terms
Related Official Resources
Continue learning straight from the source. Every link below goes to an official government or DoD resource.
Last reviewed January 2026 against the 2026 Medicare & You and TRICARE For Life handbooks.