Glossary
Prior Authorization
A plan's requirement that a provider get approval before delivering certain services or medications.
Also known as: pre-auth, preauthorization, PA
Quick answer
Prior authorization is a utilization-management process where your insurer requires advance approval for specific tests, procedures, hospital stays, or drugs before they will cover them.
Why it matters
Original Medicare requires prior authorization for very few services. Medicare Advantage plans use it heavily. For TFL beneficiaries comparing MA plans, prior-authorization burden is a major quality-of-care consideration.
When you'll encounter it
When your doctor orders advanced imaging (MRI/CT), specialist procedures, durable medical equipment, or specialty drugs under an MA plan.
Impact on Medicare
Original Medicare requires prior authorization only for limited services (some DME, certain outpatient hospital services).
Impact on TRICARE For Life
TFL itself rarely requires its own prior authorization on dual-covered claims — it follows Medicare's adjudication.
Impact on Medicare Advantage
MA plans require prior authorization for many services. Delays and denials are a common complaint and a key factor when comparing plans.
Common misconceptions
- "If my doctor orders it, my plan must pay." — Not under MA. The plan can deny payment if prior authorization wasn't obtained or criteria weren't met.
Continue learning
— suggested by the knowledge graph- 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.
- Medicare Advantage for veterans: when it makes sense and when it doesn'tCarrier-neutral education on Medicare Advantage (Part C) for retired military — including how MA changes the role of TFL.
- What is Medicare? A complete overview for retired militaryA plain-English, handbook-grounded overview of the federal health insurance program for people 65 and older, written specifically for retired service members and their families.
- Understanding Original Medicare (Parts A & B) for veteransExactly what Part A and Part B cover, what they cost in 2026, and why both are required to keep TRICARE For Life.
- Emergency Coverage (Medicare Advantage)Emergency room care is covered by MA plans nationwide — in or out of network — at the plan's emergency copay.
- Provider NetworkThe list of doctors, hospitals, and facilities that contract with an insurance plan.
- ReferralsA formal approval from your primary care physician required by some Medicare Advantage plans before you can see a specialist.
- AEP & OEP (Election Periods)AEP (Oct 15 – Dec 7) is when you can join, switch, or drop MA plans. OEP (Jan 1 – Mar 31) lets you change MA plans once.
- Annual Election Period (AEP)October 15 – December 7 each year — the main window to join, switch, or drop a Medicare Advantage or Part D plan, with coverage starting January 1.
- 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.
- How do I decide between Medicare Advantage and just Original Medicare + TFL?Stay with Original Medicare + TFL if you want maximum provider choice and travel often. Consider MA if you want a Part B giveback, dental/vision/hearing add-ons, and your doctors are in network.
- Do Medicare Advantage plans require prior authorization?More often than Original Medicare. MA plans commonly require PA for imaging, specialty drugs, certain procedures, SNF stays, and home health. Original Medicare + TFL has very few PA requirements.
- Can I use Medicare Advantage and VA healthcare at the same time?Yes. VA care doesn't bill MA, and MA doesn't bill VA. You can use VA for some services and MA (with TFL as backup) for others.
- Will I lose TRICARE For Life if I join Medicare Advantage?No. As long as you keep Medicare Part B, TFL stays. Inside an MA plan, MA becomes primary and TFL becomes a secondary wraparound for in-network MA cost-shares.
- 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.
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.