What Is Prior Authorization? A Patient's Guide to Getting Approved

Your doctor says you need an MRI. Your insurer says you need permission first.

That's prior authorization — a requirement that your insurance company sign off on a treatment before they agree to pay for it. It's one of the most frustrating parts of having health insurance in America. It delays care, creates administrative nightmares for doctors, and leaves patients stuck in the middle.

About 25% of all prescription drugs and 35% of elective procedures require prior authorization. The vast majority of those requests are eventually approved — but the process itself can take days or weeks, during which you wait, your condition potentially worsens, and your provider's office spends hours on the phone with your insurer.

This guide explains exactly how prior authorization works, what to do when it blocks your care, and how to fight back when it gets denied.

What Prior Authorization Actually Is

Prior authorization (sometimes called pre-authorization or pre-certification) is a utilization management tool that insurance companies use to verify whether a treatment or service is "medically necessary" before agreeing to cover it. It's a financial gate — not a clinical one.

The key thing to understand: your doctor orders a treatment because they believe you need it. Your insurer then reviews that order to decide if they want to pay for it. These two parties have different incentives, and the gap between them is where prior authorization lives.

Insurers argue prior auth controls costs and prevents overutilization. Critics — including a growing number of state legislatures — argue it primarily serves to delay or deny payment on valid claims while creating enormous administrative burden for doctors. Both can be true simultaneously.

Prior auth vs. referral — not the same thing

It's easy to confuse these two, but they serve different purposes:

• Referral: Your primary care physician sends you to a specialist. It's a care coordination tool. Most referrals go to in-network doctors and are about navigating your plan's network.
• Prior authorization: Your insurer approves a specific treatment, drug, or service before they pay for it. The authorization is for the procedure or medication itself, not the doctor.

Some plans require both (HMO plans often require referrals and prior auth for specialist treatments). PPO plans typically don't require referrals but still have prior auth requirements for high-cost services.

What Services Typically Require Prior Authorization

Requirements vary by insurer, plan type, and state regulation. Here's what commonly triggers a prior auth requirement across most major insurers:

Surgeries and inpatient admissions

Most elective surgeries — knee replacements, spinal fusions, bariatric procedures, hysterectomy — require prior authorization before the insurer will pay. Emergency surgeries are exempt. The prior auth for surgery also typically covers the hospital stay.

Advanced imaging

MRI, CT scans, PET scans, and some ultrasound studies often require prior authorization. Standard X-rays typically do not. The rationale is that imaging is overutilized — insurers want a clinical gatekeeper between you and a $3,000 MRI.

Specialty medications

Biologics, chemotherapy agents, specialty injectables (Humira, Enbrel, Rituxan), and some oral chemotherapy or autoimmune drugs almost always require prior authorization. Insurers often have a preferred drug list and require you to "fail first" on a cheaper alternative before approving the more expensive one.

Durable medical equipment (DME)

Wheelchairs, scooters, hospital beds, CPAP machines, and other equipment above a certain cost threshold require prior authorization. Your doctor typically needs to document the medical necessity and why a simpler option won't suffice.

Home health and skilled nursing

Home health visits, skilled nursing facility stays, and physical therapy above a certain number of visits often require prior authorization. This is a common area of denial — insurers may approve only a fraction of the visits your doctor orders.

Out-of-network services

Seeing an out-of-network provider almost always requires prior authorization or a referral from your in-network primary care physician. Without it, you're typically responsible for the full cost.

The Prior Authorization Process — Step by Step

Here's what actually happens when your doctor orders a service that requires prior auth:

Standard turnaround timelines by major insurer

Insurer	Standard Prior Auth	Expedited / Urgent	Auto-Approval (no response)
Aetna	2 days	72 hours	After deadline expires
Blue Cross Blue Shield	2 days	72 hours	Varies by state plan
Cigna	2 days	72 hours	After deadline expires
UnitedHealthcare	2–3 days	72 hours	After deadline expires
Humana	5 days	72 hours	After deadline expires

Timelines vary by state regulation and your specific plan. Always verify with the member services number on your insurance card.

What to Do When Prior Authorization Is Denied

A prior authorization denial isn't the end. It's the beginning of the formal appeals process — the same one that applies to any other insurance denial. And remember: denials on appeal succeed 40–60% of the time.

First — understand why it was denied

The denial letter should state the specific reason. Common ones:

• Not medically necessary: The insurer's clinical reviewer doesn't think the service meets their criteria. This is the most common denial reason. Your doctor's documentation — not yours — is the key to reversing it.
• Excluded service: Your plan explicitly excludes this type of treatment or drug. Check your Summary of Benefits and Coverage (SBC) to verify whether the exclusion is actually in your plan.
• Incomplete information: The insurer didn't have enough clinical documentation. This is common and often fixable — get your doctor's office to submit additional notes, clinical guidelines, and supporting studies.
• Out-of-network without authorization: You went to a provider outside your network without getting prior approval. If the provider was in-network and the denial is a billing error, your doctor's office can often reprocess it.

Appeal the denial — here's how

The prior auth denial letter is your instruction manual. It tells you how to appeal and how long you have. The process is identical to appealing a claim denial:

1. Internal appeal: Ask your doctor to write a letter of medical necessity and request a peer-to-peer review with the insurer's medical director. A peer-to-peer call — where your doctor discusses the case directly with the insurer's physician reviewer — resolves many denials without a formal appeal.
2. Submit additional documentation: Include clinical guidelines, peer-reviewed studies, your doctor's treatment history with your condition, and any prior authorizations for similar cases you've had approved before.
3. External review: If internal appeal is denied (or the insurer doesn't respond in time), request an external review by an Independent Review Organization (IRO). The insurer must accept the external reviewer's decision.

Expedited Prior Authorization — When You Can't Wait

If your condition is urgent — a physician determines that waiting for a standard prior auth decision timeline would seriously jeopardize your life, health, or ability to regain maximum function — you can request an expedited review.

Urgent/expedited prior auth must be decided within 72 hours under federal ACA rules (some states require 24–48 hours for certain cases).

What qualifies for expedited review

The standard is clinical, not administrative: "serious threat to life, health, or ability to function." Your doctor must specifically request the expedited designation — they cannot assume it applies. Common qualifying situations:

• Active cancer requiring immediate treatment start
• Cardiac catheterization or surgery scheduled
• Hospital discharge held up by authorization delay
• Specialty medication needed to prevent disease progression
• Mental health crisis where medication change is urgent

Your doctor submits the request with a statement of clinical urgency. The insurer then has 72 hours to approve or deny. They cannot require you to use the standard timeline if clinical urgency is documented.

The No Surprises Act — What It Does (and Doesn't) Do to Prior Auth

The No Surprises Act (effective January 1, 2022) provides specific patient protections around surprise billing and prior authorization. Here's what it means for prior authorization specifically:

What the No Surprises Act protects against

• Emergency care: Insurers cannot require prior authorization before paying for emergency services. You can go to the ER without worrying about a prior auth denial blocking coverage.
• Surprise bills from out-of-network providers: If you receive care from an out-of-network provider at an in-network facility, the No Surprises Act limits what you can be billed. Prior authorization cannot be used to shift liability to you in these situations.
• Continuity of care: If you're already receiving care from a provider who goes out-of-network, you may qualify for continuity of care protections that limit prior auth requirements for ongoing treatment.

What the No Surprises Act does NOT eliminate

The No Surprises Act is not a prior authorization reform law. It doesn't ban prior authorization requirements. It specifically addresses:

• Emergency situations and surprise bills from out-of-network providers
• Billing disputes at in-network facilities

Scheduled surgeries, routine imaging, specialty drugs, and non-emergency services still commonly require prior authorization. For those situations, state-level prior authorization reform laws (growing in number) are what actually change the process.

Several states have passed prior authorization reform laws — including requirements for faster turnaround, gold-carding (doctors who get approvals frequently get automatic approval for future requests), and transparency on denial reasons. Check your state's insurance department website for current regulations.

How to Avoid Prior Authorization Delays in the First Place

Most prior authorization problems happen not because the request was denied, but because it was incomplete, submitted to the wrong place, or lost in the insurer's system. Here's how to reduce friction:

• Know your plan's formulary and prior auth list. Your insurer's website has a current list of services requiring prior authorization. Know it before scheduling a procedure.
• Have your doctor's office submit proactively. If your doctor knows a procedure requires prior auth, ask them to submit it before you even schedule the treatment. Get the authorization number before scheduling.
• Document everything. Get the prior auth number in writing. Save the submission timestamp, the agent's name you spoke to, and the confirmation number. If the insurer loses the request, you have proof of when it was submitted.
• Follow up weekly. Prior auth requests can sit in review queues for days. Call your insurer every few days to check status. Call your provider's office — their system may show a status update yours doesn't.
• Use your insurer's clinical staff as a resource. Some insurers have nurse care managers who can help navigate prior auth for complex conditions. Ask if this is available.

Prior Authorization for Prescription Drugs — A Separate Track

Drug prior authorization works slightly differently than medical service prior authorization. The pharmacy or your doctor's office submits a prior auth to the insurer's pharmacy benefit manager (PBM) rather than the medical insurer.

Common drug prior auth triggers:

• Brand-name drug when a generic is available (insurer requires you to try the generic first)
• Specialty medication above a certain price threshold
• Drug for an "off-label" use not typically covered
• Quantity exceeding the insurer's maximum (e.g., more than a 30-day supply for certain controlled substances)

Your pharmacist typically notifies you at the pharmacy counter if a prior auth is needed. They contact your doctor's office, the doctor submits the auth request, and you wait. This process can take 1–3 days. In the meantime, some pharmacies will dispense a short-term supply while the auth processes (typically for an urgent medication).