You and your doctor agree on a treatment, a scan, or a medication, and then the pharmacy or clinic tells you it is on hold until your insurance company approves it. That approval step is called prior authorization, and it is one of the most common sources of delays and frustration in American health care. Knowing how prior authorization works, who is responsible for each step, and how to appeal a denial can help you get the care you need sooner and avoid paying for services your plan should cover.
What Prior Authorization Means
Prior authorization, also called preauthorization, precertification or prior approval, is a requirement that your health plan agrees a service or drug is medically necessary before it will cover it. Without the approval, the plan may refuse to pay, even if the service would otherwise be a covered benefit.
Plans say prior authorization helps control costs and ensure treatments follow clinical guidelines. Critics, including many physician groups, argue it delays care and adds administrative burden. Whatever your view, if your plan requires it, the rule affects whether your claim is paid.
Services That Commonly Require It
Every plan keeps its own list, but prior authorization is frequently required for:
- Advanced imaging, such as MRI, CT and PET scans.
- Planned inpatient admissions and many outpatient surgeries.
- Specialty and brand-name drugs, including many injectable medications.
- Durable medical equipment, such as certain wheelchairs or home devices.
- Some physical therapy, behavioral health and home health services beyond a set number of visits.
Emergency care generally does not require prior authorization. Federal law requires most plans to cover emergency services without prior approval, whether the provider is in or out of network.
Who Does What in the Process
Your Provider Usually Submits the Request
In most cases, your doctor's office submits the request to the plan with clinical notes, test results and the reason for the treatment. If you see an in-network provider, the provider is generally responsible for obtaining authorization, and in many plans you cannot be billed if they fail to do so. If you use an out-of-network provider, you may be responsible for obtaining it yourself.
The Plan Reviews It
A clinical reviewer at the plan compares the request against coverage criteria. The plan may approve the request, deny it, approve a modified version, or ask for more information.
You Receive a Decision
If the plan denies the request, it must explain why in writing and describe your appeal rights. Keep this letter, because the reason given shapes your appeal.
How Long Decisions Take
Timelines depend on the type of plan and whether the request is urgent. Federal rules for many private plans set maximum response times, with faster deadlines for urgent care. For Medicare Advantage, Medicaid managed care, CHIP and plans on the federal marketplace, a federal rule that took effect in 2026 generally requires decisions within 72 hours for expedited requests and seven calendar days for standard requests, along with clearer explanations of denials. If your health could be seriously harmed by waiting, ask your provider to request an expedited review.
Practical Steps Before Treatment
You can reduce the chance of a delay by taking a few steps early:
- Ask your provider whether the service needs prior authorization and who will request it.
- Call the number on your insurance card to confirm the requirement and the status of the request.
- Get the authorization number and the approved dates, number of visits, or quantity of medication.
- Check whether the approved provider and facility are in network. Our guide to the deductible and out-of-pocket maximum explains why network status affects your costs.
Step Therapy and Formulary Rules
For prescription drugs, prior authorization often overlaps with step therapy, a rule that requires you to try a lower-cost medication first. If you have already tried the alternative, cannot tolerate it, or it is clinically inappropriate, your doctor can request an exception. Many states have laws that require plans to grant step therapy exceptions under defined circumstances.
How to Appeal a Denial
Step 1: Read the Denial Carefully
Identify the exact reason. Common reasons include missing documentation, failure to meet criteria, the plan considering the treatment experimental, or a coding problem. A paperwork issue can often be fixed quickly.
Step 2: Ask for a Peer-to-Peer Review
Your doctor can often request a conversation with the plan's medical reviewer. A short discussion of your history can resolve a denial faster than a formal appeal.
Step 3: File an Internal Appeal
If the denial stands, file a written internal appeal within the deadline in your letter. Under the Affordable Care Act, most plans must allow at least 180 days to file an internal appeal of a denied claim. Include:
- A letter from your doctor explaining medical necessity.
- Relevant records, test results and notes about treatments already tried.
- Clinical guidelines or published research that support the treatment.
- A copy of the denial letter and your plan's coverage language.
Step 4: Request an External Review
If the internal appeal fails, most plans must let you request an independent external review. The reviewer is not employed by your insurer, and if they overturn the denial, the plan must generally follow the decision. Your state insurance department or the federal external review process can explain how to file.
If You Have Employer Coverage
Self-funded employer plans are governed by federal law rather than state insurance rules, so different appeal processes may apply. Ask your human resources department or plan administrator for the Summary Plan Description, which lists the procedures and deadlines.
Keep a Record of Everything
Write down the date, time, name of the representative and reference number for each call. Save copies of every letter and form. Detailed records make appeals stronger and help if you need to complain to your state insurance department. Financial preparation also helps: an emergency cushion in a high-yield savings or money market account can prevent a delayed approval from turning into debt.
The Bottom Line
Prior authorization is a plan's advance approval of a service or drug. Your provider usually handles the request, but you can speed things up by confirming requirements, tracking authorization numbers, and acting quickly on denials. Many denials are overturned on appeal, so do not accept the first answer if you and your doctor believe the treatment is necessary.
Frequently Asked Questions
Who is responsible for getting prior authorization?
In-network providers usually request it on your behalf. If you use an out-of-network provider, you may need to request it yourself. Confirm with both the provider and your plan.
What happens if I get care without required prior authorization?
The plan may deny the claim. If an in-network provider failed to obtain approval, many plans prohibit the provider from billing you, but check your plan rules and contest the bill if needed.
Do emergencies require prior authorization?
Generally no. Most plans must cover emergency services without prior approval, regardless of whether the hospital is in network.
How successful are prior authorization appeals?
Outcomes vary by plan and case, but many denials are overturned when the provider submits complete documentation. It is usually worth appealing a denial you believe is wrong.