Pre-authorization (also called prior authorization or precertification) is a requirement from your health insurance plan that your doctor get approval before providing certain services, treatments, or medications. The insurer reviews whether the care is medically necessary before agreeing to cover it. It’s one of the most common gatekeeping tools in medical billing, and it affects everything from MRI scans to prescription drugs.
One important detail many people miss: getting pre-authorization is not a guarantee of payment. It confirms the insurer considers the service medically necessary at that point in time, but the final claim can still be denied for other reasons, like a lapsed policy or incorrect billing codes.
How Pre-Authorization Works
The process starts when your doctor determines you need a specific service or medication. Before scheduling or prescribing it, your doctor’s office contacts your insurance company (by phone, fax, or electronic portal) and submits clinical documentation explaining why the care is necessary. This might include your diagnosis, medical history, imaging results, or notes from previous treatments that didn’t work.
The insurance company reviews that information and makes a decision: approve, deny, or request more documentation. For non-urgent requests, insurers have generally taken anywhere from a few days to several weeks to respond. A 2024 federal rule from the Centers for Medicare and Medicaid Services now requires most affected payers to respond within 72 hours for urgent requests and seven calendar days for standard requests, with implementation beginning in 2026.
If the request is denied, your doctor can appeal or submit additional information. You also have the right to appeal the decision yourself through your plan’s grievance process.
Services That Typically Require It
Not every doctor visit or lab test needs pre-authorization, but many higher-cost or specialized services do. Common categories include:
- Hospital admissions and stays at skilled nursing facilities
- Planned surgeries, including both elective and medically necessary procedures
- Advanced imaging like MRIs and CT scans
- Durable medical equipment such as portable oxygen tanks, wheelchairs, or infusion pumps
- Specialty medications, particularly those that are expensive, carry serious side effects, have abuse potential, or could interact dangerously with other drugs
Medicare has its own specific list. For hospital outpatient services, procedures currently requiring prior authorization include cosmetic-adjacent surgeries (eyelid lifts, nose reshaping, excess skin removal), vein treatments, spinal neurostimulator implants, certain spinal fusions, and spinal joint injections. Private insurers each maintain their own lists, which can vary significantly from plan to plan.
Emergency care is the major exception. Insurers cannot require pre-authorization before you receive emergency treatment, though they may review the claim afterward.
What Happens Without It
If a service that requires pre-authorization is performed without it, the claim will almost certainly be denied. Insurance companies use specific denial codes to flag these situations, and the language on the explanation of benefits you receive will reference missing, invalid, or expired authorization numbers. Some common reasons for denial include the authorization number not matching the billed service, the authorization having expired before the service was provided, or the request simply never being submitted.
When a claim is denied for missing pre-authorization, the financial consequences can fall on you. Depending on your plan and state law, you could be responsible for the full cost of the service. In some cases, your doctor’s office may absorb the cost or help you file an appeal, but there’s no universal rule protecting you here. This is why confirming authorization status before any scheduled procedure matters so much.
The Administrative Burden
Pre-authorization creates significant work for medical practices. According to American Medical Association survey data, the average physician’s practice completes 39 prior authorization requests per week, per doctor. That volume translates to staff hours spent on hold with insurers, filling out forms, and tracking down clinical records to justify care the physician has already determined is necessary.
The process also delays care. When an insurer takes days or weeks to respond, patients wait for surgeries, imaging, and medications their doctors have already prescribed. The AMA has documented cases where those delays led directly to worse health outcomes, and the organization has pushed for legal accountability when insurer delays or denials cause patient harm. The opacity of the denial process compounds the frustration: insurers have historically denied requests without clearly explaining their reasoning or suggesting covered alternatives, leaving doctors and patients guessing at what the plan will actually pay for.
New Federal Rules Changing the Process
The CMS Interoperability and Prior Authorization Final Rule, released in January 2024, represents the most significant federal effort to streamline pre-authorization in years. The rule targets Medicare Advantage plans, Medicaid managed care plans, and certain other federally regulated payers.
Starting primarily in 2026, these payers must meet the 72-hour and seven-day response deadlines mentioned earlier. By January 2027, they’ll also need to support electronic prior authorization through modern data-sharing technology, replacing the patchwork of fax machines, phone calls, and proprietary portals that many practices still navigate today. The goal is to reduce the back-and-forth that currently bogs down the system for providers, payers, and patients alike.
These rules don’t cover every insurer. Employer-sponsored plans regulated under federal law (ERISA plans) and some state-regulated commercial plans may not be directly affected, though many states have been passing their own prior authorization reform laws with similar timelines and transparency requirements.
How to Protect Yourself
Before any scheduled procedure, imaging test, or new specialty medication, call your insurance company and ask whether pre-authorization is required. Don’t assume your doctor’s office has handled it, even though they usually do. Confirm that the authorization has been approved and note the reference number.
If your request is denied, ask for the denial in writing with a specific reason. You have the right to appeal, and your doctor can submit additional clinical documentation to support the case. Many denials are overturned on appeal, particularly when the initial submission lacked sufficient detail.
Check whether your authorization has an expiration date. If your surgery gets rescheduled or a medication refill is delayed, the original authorization may lapse, and you’ll need a new one. Keeping a simple log of authorization numbers, approval dates, and expiration dates can save you from unexpected bills down the line.