Authorization in healthcare — most commonly called prior authorization, preauthorization, or precertification — is the process by which a health insurance company must approve a proposed treatment, medication, procedure, or diagnostic test before it is provided. Without that approval, the insurer is not obligated to pay for the service, leaving the financial responsibility on the patient or, in some cases, the provider.
It is one of the most consequential and most contested processes in the American healthcare system. A 2024 American Medical Association survey found that the average medical practice completed 43 prior authorizations per physician per week, with physicians and staff spending approximately 12 hours per week on the paperwork. At the same time, about 73% of American adults say that insurance-related delays and denials are a major problem. Understanding how the process actually works gives patients a meaningful advantage in navigating it.
Why Insurance Companies Require Authorization
Insurers require authorization for several stated reasons. They use it to confirm that the proposed care is covered under the patient’s specific plan, to evaluate whether the care is medically necessary as defined by their clinical criteria, and to ensure that cost-effective alternatives have been considered before a more expensive treatment is approved.
In practice, cost containment is the central driver. Insurers use authorization to redirect patients toward lower-cost generic drugs instead of brand-name medications, toward in-network facilities rather than out-of-network hospitals, and toward less expensive first-line treatments before approving specialized or newer therapies. The requirement to try a less expensive treatment first before a more complex one is approved is called step therapy, and it is one of the more frustrating manifestations of the authorization system from a patient perspective — particularly when a physician has already determined that the first-line option is inappropriate for a specific patient.
What Services Typically Require Authorization
Not all healthcare services require prior authorization. Routine primary care visits, most preventive services, and emergency care are generally exempt. Authorization requirements are concentrated in higher-cost, specialized, or potentially discretionary services.
Common categories requiring prior authorization include specialty medications and biologics, particularly new or brand-name drugs with lower-cost alternatives; medical imaging including MRI, CT scans, and PET scans; elective surgical procedures; inpatient hospitalizations and extended stays; mental health and substance use disorder treatment beyond initial visits; durable medical equipment including wheelchairs, CPAP machines, and orthotics; and certain diagnostic tests. Emergency care does not require prior authorization — insurers cannot delay emergency treatment pending approval.
The specific list of services requiring authorization varies by insurer, plan type, and state. What requires authorization under one plan may not under another, even within the same insurance company. This variability is itself a source of confusion for both patients and providers.
How Does the Prior Authorization Process Work?
The process begins with the treating physician or provider, not the patient. When a provider determines that a patient needs a service that requires prior authorization, they submit a request to the insurer with supporting clinical documentation explaining why the service is medically necessary for that specific patient.
The insurer then reviews the request. Standard requests must be processed within a defined timeframe — under the CMS Interoperability and Prior Authorization Final Rule, finalized in 2024 and effective January 2026, the standard review period is being reduced to 7 calendar days for Medicare Advantage, Medicaid, CHIP, and Marketplace plans. Expedited or urgent requests must receive a decision within 72 hours. The insurer will either approve the request, deny it, or request additional clinical information before making a decision.
If approved, the authorization is valid for a defined period — typically 30 to 180 days depending on the service — after which reauthorization may be required for ongoing treatment. A prior authorization for a medication does not mean unlimited refills; it expires and must be renewed.
If denied, the patient and provider both receive written notice explaining the reason for denial. This denial is not final.
What Happens When Authorization Is Denied?
A denial is the beginning of a process, not the end of the road. Patients and providers have the right to appeal denied prior authorization decisions, and appeals are frequently successful — particularly when supported by clinical documentation demonstrating medical necessity.
The appeal process typically begins with an internal appeal to the insurer, where the denial is reviewed by a clinical professional at the insurer who was not involved in the original decision. If the internal appeal is denied, most plans allow an external appeal to an independent review organization that evaluates the case without ties to either the insurer or the provider. In Medicare Advantage specifically, if the plan upholds a denial after the initial appeal, the case is automatically sent to an independent review entity — which has contributed to Medicare Advantage’s 82% appeal overturn rate, far higher than the 36% overturn rate seen in Medicaid managed care organizations.
The most effective appeals are built on specific, documented clinical evidence that the denied treatment is medically necessary for the specific patient — not just generally appropriate. Physician letters, treatment guidelines from professional medical societies, peer-reviewed literature supporting the treatment, and documentation of why alternatives are inappropriate all strengthen an appeal.
Is Authorization the Same as a Guarantee of Coverage?
No, and this distinction matters. Prior authorization confirms that an insurer has pre-approved a service as meeting its medical necessity criteria at the time of review. It does not guarantee payment. After the service is provided, the insurer still processes the claim through normal billing, and the final payment can be affected by whether the correct billing codes were used, whether all services rendered match what was pre-approved, whether the patient’s coverage has changed, and whether cost-sharing obligations like deductibles and copays have been met.
Receiving prior authorization and then receiving a denial on the resulting claim — while frustrating — is legally and contractually possible under current rules. This is an important distinction for patients to understand when planning the financial side of a procedure.
The Authorization Burden on Physicians and Patients
The administrative weight of prior authorization has become one of the most significant drivers of physician burnout in American medicine. An AMA survey found that 94% of physicians reported prior authorization delays care, and 78% reported it has led patients to abandon a recommended course of treatment altogether. The time spent on authorization paperwork by physicians and staff — averaging 12 hours per week per physician in 2024 — is time not spent on patient care.
For patients, the consequences are more direct: delayed treatment, disrupted medication regimens when refills are denied, and the financial exposure of receiving care that a provider initiated before realizing authorization was required.
In response to growing pressure from physicians, patient advocates, and lawmakers, a voluntary initiative announced in June 2025 saw approximately 50 major health insurers pledge to reduce the number of services requiring prior authorization, speed up review timeframes, and simplify the submission process. CMS Administrator Mehmet Oz called the move a step toward restoring trust between insurers and providers. The American Medical Association, while acknowledging the pledge, noted that physicians need to see specific, measurable outcomes rather than general commitments.
How Do AI and Technology Affect Authorization Decisions?
The use of artificial intelligence in prior authorization processing has become both a growing practice and a growing controversy. Humana and UnitedHealth have both faced lawsuits alleging that AI algorithms were used to wrongfully deny care to Medicare Advantage members by identifying statistical patterns that predicted high recovery likelihood and auto-denying cases that exceeded predicted timelines — without individual clinical review. Both insurers have stated they do not use AI to deny care.
The CMS Interoperability and Prior Authorization Final Rule requires that prior authorization decisions affecting real clinical outcomes continue to be reviewed by qualified clinical professionals, and explicitly limits fully automated decision-making in denial contexts. The use of AI as a tool to assist human reviewers in finding relevant information is permitted; using it as the decision-maker is not.
Authorization in Massachusetts: What Boston Patients Should Know
Massachusetts has been an active state in regulating prior authorization requirements. Massachusetts law requires insurers to respond to urgent prior authorization requests within 72 hours and to standard requests within a defined window. The state’s Division of Insurance oversees insurer compliance with authorization rules and accepts complaints from patients who believe their insurer has not followed required procedures.
For patients navigating prior authorization denials in Massachusetts, the Health Insurance Consumer Assistance Program offers free help with appeals and complaints. Boston’s major academic medical centers — Massachusetts General Hospital, Brigham and Women’s, and Boston Medical Center — have dedicated patient authorization and financial counseling teams who can assist patients in initiating and managing the authorization process.
If you receive a denial, the Massachusetts Division of Insurance can provide guidance on your specific rights under state law and can help you file a complaint if an insurer is not following required timelines or appeal procedures.
Practical Steps for Patients Dealing With Prior Authorization
Before a procedure or prescription: Ask your provider explicitly whether the service requires prior authorization and confirm they are submitting the request. Do not assume the provider’s office is handling it without checking. Ask for the authorization reference number once submitted.
If you are denied: Read the denial letter carefully. The reason for denial is clinically and legally specific — it matters whether you were denied because the service is not covered, because medical necessity was not established, or because step therapy requirements were not met. Each requires a different appeal strategy.
Work closely with your provider: The most successful appeals combine a provider’s clinical narrative with objective documentation. Ask your physician to write a letter of medical necessity that specifically addresses the insurer’s stated reason for denial.
Know your timeframes: In urgent situations, request an expedited appeal. Most states mandate insurer responses to expedited appeals within 72 hours.
For comprehensive guidance on navigating health insurance decisions and your rights as a patient under federal and state law, HealthCare.gov’s Know Your Rights resource provides current information on protections available to insured Americans.
Frequently Asked Questions
Does prior authorization mean my insurance will definitely pay?
No. Prior authorization confirms medical necessity approval before the service, but final payment depends on billing accuracy, plan terms, cost-sharing requirements, and whether coverage has changed since authorization was granted.
Can a hospital or provider start treatment without prior authorization?
In emergencies, yes — emergency care cannot be delayed pending authorization. For non-emergency services, providers typically wait for authorization because without it, the insurer may refuse to pay and the cost falls to the patient or provider.
What is the difference between prior authorization and a referral?
A referral is a physician’s direction to see a specialist and is an administrative step within the care coordination process. Prior authorization is a separate insurance approval requirement for specific services or medications. Some plans require both — a referral from a primary care physician and an insurer’s prior authorization — for specialist visits or procedures.
