What Is Prior Authorization — and How Do You Survive It?
Your doctor says you need an MRI. You schedule it, show up, and get a call two days later: your insurance is denying it because nobody got "prior authorization" first. The scan hasn't happened yet and it's already being rejected.
Or your doctor calls in a new medication and the pharmacy tells you it'll be $800 without approval from your insurer. You had no idea approval was needed.
This is prior authorization — one of the most frustrating mechanisms in the US healthcare system, and one of the least understood. Here's exactly how it works, why it exists, which services trigger it, and how to move a stuck PA forward without waiting weeks.
What prior authorization actually is
Prior authorization (PA) — also called pre-authorization, pre-approval, or pre-certification — is a requirement by your health insurer that your doctor gets permission before certain treatments, procedures, medications, or referrals will be covered.
In theory, it is a cost-control mechanism designed to ensure that expensive or potentially unnecessary care is medically justified before it happens. In practice, it is one of the most significant sources of treatment delays in US healthcare — and one of the most frequently abused tools insurers use to avoid paying for care they are contractually obligated to cover.
Prior authorization is not a clinical decision. It is an administrative one. The person reviewing your PA request at the insurance company is not your doctor, has not examined you, and does not have your full medical history. They are checking your request against a set of clinical criteria — and those criteria can be challenged. That's what this guide is for.
What services commonly require prior authorization
Every insurance plan maintains its own list of services that require PA — and these lists change regularly. The following categories almost universally require it:
Never assume a service doesn't require PA just because your doctor ordered it. Your doctor's office may not know your plan's specific requirements — and the financial responsibility for services provided without required authorization almost always falls on you. Always call the member services number on the back of your insurance card and ask specifically: "Does this service require prior authorization under my plan?"
How the prior authorization process works
Understanding the actual sequence helps you know where delays happen and where you can intervene.
PA approval does not guarantee payment. It means the service is pre-approved as medically necessary — but if something else goes wrong (wrong billing code, out-of-network provider, plan exclusion), your claim can still be denied after the fact. Always verify the approval letter specifies the exact service, provider, and date range covered.
How to check if your service needs prior authorization
What to do when a PA is stuck or taking too long
The most common PA problem isn't a denial — it's silence. The request was submitted, nothing has come back, and your appointment or prescription is in limbo. Here is how to move it.
Call your doctor's office first — not your insurer
The first question is whether the PA was actually submitted. A surprising number of delays happen before the request even reaches the insurer. Ask the medical assistant or billing coordinator: "Can you confirm the PA request was submitted, what date it was sent, and what reference number was assigned?"
Call your insurer with the reference number
Once you have the reference number, call the member services number on your insurance card and ask for the PA department. Use this script:
"I'm calling to check the status of a prior authorization request submitted by my doctor's office. The reference number is [NUMBER]. It was submitted on [DATE] for [SERVICE/MEDICATION]. Can you tell me where it stands in the review process, whether any additional information has been requested, and when I can expect a decision?"
Ask if additional documentation was requested
The most common reason a PA sits in "pending" status is that the insurer requested more clinical information from your doctor's office and the request went unanswered. Ask the insurer: "Has any additional documentation been requested? If so, what exactly, and when was it requested?" Then call your doctor's office immediately with that information.
Ask your doctor to request a peer-to-peer review
This is the most powerful tool available when a PA is denied or stuck. A peer-to-peer review is a direct conversation between your doctor and the insurer's medical reviewer. Studies consistently show that peer-to-peer reviews overturn PA denials at a high rate — because it is much harder for a reviewer to deny a request when a treating physician is explaining the clinical rationale in real time.
Peer-to-peer review requests must be made by your doctor — not you. But you can and should ask your doctor to request one. Say: "I know PA requests can be appealed through a peer-to-peer call with the insurer. Would you be willing to request one if my PA is denied?" Most doctors are familiar with this process and will say yes.
Request an urgent / expedited review if your condition warrants it
If waiting for a standard PA decision would seriously jeopardize your health, you or your doctor can request an expedited review. Insurers are legally required to decide expedited PA requests within 72 hours. Ask both your doctor's office and your insurer about this option if your situation is time-sensitive.
What to do if your PA is denied
A PA denial — like a claims denial — is not final. You have the right to appeal, and the appeal process for a PA denial works similarly to a claims denial appeal.
- Request the denial in writing — the letter must state the specific reason and the clinical criteria used
- Ask your doctor for a peer-to-peer review — this is the first and most effective step, before a formal appeal
- File a formal internal appeal — submit your doctor's Letter of Medical Necessity along with any supporting clinical literature
- Request an expedited appeal if your condition is urgent — decisions required within 72 hours
- Request an external review if the internal appeal fails — an independent reviewer makes a binding decision your insurer must comply with
According to the American Medical Association, more than 80% of PA denials that go through a peer-to-peer review or formal appeal are ultimately approved. The initial denial is frequently a first-pass rejection based on incomplete documentation — not a final clinical judgment. Appealing is almost always worth doing.
The phone call checklist — what to document every time
Every time you call your insurer or doctor's office about a PA, document the following before you hang up:
- Name of the person you spoke with
- Date and time of the call
- Reference number for the PA request
- Current status of the PA (pending, approved, denied, more info needed)
- What additional documentation was requested, if any
- Expected decision date
- Name of the clinical criteria or guidelines being used to review the request
- Whether a peer-to-peer review has been requested or is available
PA approvals expire. Most are approved for a specific service window — 30, 60, or 90 days, or a specific date of service. If your appointment is rescheduled outside that window, you may need a new PA. Always confirm the approval expiration date and make sure your scheduled date falls within it.
A word on what's changing
Prior authorization has been under significant regulatory scrutiny. In 2024, a final rule from CMS introduced new requirements for Medicare Advantage and Medicaid managed care plans — including shorter decision timeframes, electronic PA requirements, and restrictions on the ability to deny care that meets established clinical criteria. Legislation targeting commercial insurance PA requirements has also been advancing in multiple states.
The system is not fixed. But it is changing — and patients who understand how it works are far better positioned to navigate it in the meantime.
The bottom line
Prior authorization is a required administrative hurdle your insurer puts between your doctor's order and your care. It is frustrating, sometimes clinically indefensible, and deliberately opaque. But it is navigable — if you know where the leverage is.
The leverage is documentation, persistence, and the peer-to-peer review. Most PA problems are not outright denials — they are requests sitting in pending because someone at the insurer is waiting for a call back from someone at your doctor's office. Your job is to be the thing that unsticks that loop.
Check that the PA was submitted. Get the reference number. Call the insurer with it. Ask what's pending. Call your doctor with that answer. Repeat until it moves. And if it's denied, ask your doctor immediately about a peer-to-peer review before you do anything else.