How Prior Authorization Systems Work

According to an American Medical Association survey, physicians complete an average of 41 prior authorization requests per week. Across the U.S. healthcare system, that amounts to hundreds of millions of prior authorization decisions annually, each one standing between a doctor's recommendation and a patient's access to care. Kaiser Family Foundation data indicates that approximately 9% of in-network prior authorization requests are denied outright, a figure that translates into millions of delayed or blocked treatments every year.

Your doctor prescribes a medication, but the pharmacy says it requires prior authorization. Your surgeon schedules a procedure, then tells you insurance must approve it first. Days or weeks later, you may get approval, denial, or approval for something different. Prior authorization inserts a gatekeeper between your doctor's recommendation and your ability to receive care. This analysis is based on publicly available physician survey data from the AMA, CMS regulatory documents, and health plan performance data published by the Kaiser Family Foundation.

Prior authorization has become ubiquitous in American healthcare. Originally intended for expensive or potentially inappropriate treatments, it now covers common medications and routine procedures. An AMA survey found that 85% of physicians report the burden of prior authorization has increased over the past five years, reflecting the system's steady expansion.

This article explains how prior authorization works, why it's expanded so dramatically, and what happens when authorization is denied.

What Prior Authorization Systems Are Meant to Do

Prior authorization requires insurers to approve certain treatments before they're provided. The stated purpose is ensuring treatments are medically necessary, appropriately used, and cost-effective. By reviewing before treatment, insurers can redirect care toward preferred alternatives or deny inappropriate requests.

From the insurer perspective, prior auth prevents unnecessary care and steers utilization toward less expensive options. When a generic medication works, requiring prior auth for the brand name encourages generic use. When physical therapy might help before surgery, prior auth can require trying it first.

The system also addresses safety concerns. Some treatments carry risks that warrant verification of appropriate indication and monitoring. Prior authorization can ensure that dangerous drugs are used appropriately and that high-risk procedures are performed only when clinical criteria are met.

It is worth noting that the scope of prior authorization has expanded significantly beyond its original intent. What began as a mechanism targeting a narrow set of expensive or high-risk treatments now extends to routine imaging, common medications, and standard outpatient procedures. This expansion has been driven by insurers seeking broader utilization management tools, but it has also generated significant pushback from physicians, patients, and state legislators who argue that the administrative costs and care delays now outweigh the savings.

How Prior Authorization Actually Works in Practice

Requirement identification: When your provider orders a treatment, their system checks whether prior auth is required. This depends on your specific insurance plan and the treatment ordered. Lists of prior auth requirements change frequently and vary between insurers. A single physician practice accepting multiple insurance plans may need to check dozens of different prior auth requirement lists, each with different criteria and submission processes.

Request submission: Your provider's staff submits the authorization request, including diagnosis, treatment requested, and clinical justification. Some insurers use electronic submission; others require faxes or phone calls. The documentation burden falls on providers. The average prior authorization request takes approximately two business days for a standard decision, but complex cases involving specialist treatments or high-cost drugs can take two weeks or more.

Review process: Insurer staff review the request against clinical criteria, often using proprietary guidelines such as InterQual (developed by Change Healthcare) or MCG Health (formerly Milliman Care Guidelines). Initial review may be by nurses or pharmacists, with denials escalated to physician reviewers. These clinical criteria define what the insurer considers medically necessary for a given diagnosis and set of circumstances, but they are often not shared with providers or patients.

Decision communication: The insurer communicates approval, denial, or request for more information. Approvals may be for limited durations, requiring reauthorization. Denials include reasons and appeal rights, though reasons are often vague.

Appeals: Denied requests can be appealed, often through peer-to-peer review where your doctor speaks with the insurer's physician reviewer. Multiple appeal levels may be available, similar to claims appeals.

Why Prior Authorization Feels Burdensome or Harmful

Delays are common. Prior authorization takes days to weeks. During this time, patients wait for needed treatments. For urgent situations, delays can cause harm. Even non-urgent delays cause pain, anxiety, and disease progression.

Administrative burden is enormous. Physicians and staff spend hours weekly on prior auth requests and appeals. With physicians completing an average of 41 prior authorizations per week, the cumulative time diverted from patient care is staggering. The cost of compliance is borne by providers but ultimately by patients through reduced access and higher overhead costs passed along in pricing.

Denials happen even when treatment is appropriate. Prior auth denials don't always reflect clinical judgment. They may result from documentation technicalities, reviewer error, or overly rigid criteria. In AMA surveys, 34% of physicians report that prior authorization has led to a serious adverse event for a patient in their care, including hospitalization, life-threatening complications, or disability.

Requirements change without notice. Drugs or procedures previously covered may suddenly require prior auth. Patients stable on medications may face disruption when authorizations expire or requirements change. The instability creates anxiety and interruptions.

The process is opaque. Patients often don't know prior auth is happening until something goes wrong. The criteria used for decisions aren't transparent. Denial reasons are vague. The system operates in a black box.

Real-World Example: Prior Authorization for a Knee MRI

Consider a patient named Michael who has been experiencing persistent left knee pain for several months. His primary care physician examines him, suspects a meniscus tear, and orders an MRI of the left knee. What follows illustrates the prior authorization process from start to finish, including a denial and successful appeal.

Step 1: The order triggers a PA requirement. When Michael's doctor enters the MRI order into the electronic health record system, the system checks his insurance plan's prior authorization requirements. Michael's insurer requires prior authorization for all advanced imaging, including MRI, CT, and PET scans. The order is flagged, and the physician's office staff must submit a PA request before the MRI can be scheduled.

Step 2: The practice submits the PA request. A staff member in the doctor's office compiles the required information: Michael's diagnosis (M23.21, derangement of posterior horn of medial meniscus, left knee), the requested service (MRI of the left knee without contrast, CPT code 73721), the clinical justification (persistent knee pain with positive McMurray test on exam, not responsive to NSAIDs), and the physician's NPI number. The request is submitted through the insurer's online portal, though some insurers still require fax submissions.

Step 3: Clinical criteria review. The insurer's utilization management team receives the request and evaluates it against their clinical criteria, in this case based on MCG Health guidelines for diagnostic imaging. The criteria specify that advanced imaging of the knee is considered medically necessary when the patient has completed a course of conservative treatment, typically defined as 4 to 6 weeks of physical therapy, rest, or anti-inflammatory medication, and symptoms persist. The insurer's nurse reviewer notes that while Michael has taken NSAIDs, there is no documentation of a formal physical therapy referral.

Step 4: Initial denial. The insurer denies the prior authorization request. The denial letter states that the MRI is "not medically necessary at this time" because "conservative treatment has not been adequately attempted." The letter advises Michael and his doctor that physical therapy should be tried before advanced imaging is authorized. The denial includes appeal instructions and a 30-day deadline for the first-level appeal.

Step 5: The physician prepares an appeal. Michael's doctor is frustrated because he believes the clinical exam findings strongly suggest a tear that physical therapy alone will not resolve. However, the doctor also recognizes that the insurer's criteria were not met on paper. He refers Michael to physical therapy, and Michael completes six weeks of treatment. His symptoms persist. The doctor's office resubmits the PA request with updated documentation: the original clinical findings, the physical therapy records showing six sessions completed without improvement, and a letter from the physician explaining the clinical rationale for imaging.

Step 6: Peer-to-peer review and approval. Rather than simply resubmitting through the portal, the doctor requests a peer-to-peer review, a phone call between Michael's physician and the insurer's medical director. During the call, the two physicians discuss the case. Michael's doctor explains the exam findings, the failed conservative treatment, and his concern about a surgical meniscus tear. The insurer's physician agrees that the criteria are now met and approves the MRI. The entire process, from the initial order to the final approval, has taken approximately eight weeks.

Michael's case is not unusual. It illustrates how prior authorization criteria can delay medically appropriate care, how documentation requirements may not align with clinical judgment, and how persistence through the appeal process, particularly through peer-to-peer review, can ultimately secure approval.

Common Myths About Prior Authorization

Myth: Prior authorization means your doctor ordered something unnecessary.
Reality: Prior authorization is a coverage determination, not a clinical judgment about medical necessity in the traditional sense. Insurers apply standardized criteria that may not account for individual patient circumstances. A denial means the request did not meet the insurer's specific documentation or step-therapy requirements, not that the treatment is inappropriate. Many denied requests are ultimately approved on appeal when additional documentation is provided.

Myth: Your doctor handles the entire PA process and knows the requirements.
Reality: Prior auth requirements vary by insurer, by plan within the same insurer, and change frequently throughout the year. Providers cannot memorize requirements for every plan they accept. Failures to obtain prior auth sometimes reflect the sheer complexity of tracking hundreds of different requirement lists rather than provider negligence. The administrative work typically falls on office staff, not the physician personally.

Myth: Once approved, you are covered for as long as you need the treatment.
Reality: Prior authorizations typically expire after a defined period, which might be a single prescription refill, 90 days, one year, or one course of treatment. Patients with chronic conditions requiring ongoing medications or therapies face repeated authorization cycles. A medication approved this year may require reauthorization next year, and the criteria may have changed in the interim.

Myth: Prior authorization only applies to expensive or unusual treatments.
Reality: While prior authorization was originally targeted at high-cost or high-risk treatments, it has expanded to cover common services. Routine imaging like MRIs, standard medications including some generics, and common outpatient procedures frequently require prior authorization. The scope of what requires PA varies significantly by insurer and plan.

Myth: If you are willing to pay out of pocket, prior authorization does not matter.
Reality: Prior authorization is about insurance coverage, not personal finances. You can choose to pay out of pocket and bypass the PA process, but those costs typically will not count toward your deductible or out-of-pocket maximum. Additionally, some pharmacies and facilities may still require a valid PA before providing the service, even if you intend to self-pay, because their billing systems are configured to check authorization status.

How to Navigate This System More Effectively

Tip: Ask your doctor's office whether a prescribed treatment requires prior authorization before you leave the appointment. Knowing upfront allows you to plan for potential delays and follow up proactively rather than discovering the requirement when you arrive at the pharmacy or imaging center.

Tip: If your prior authorization is denied, request the specific clinical criteria the insurer used to make the decision. Under CMS rules for Medicare Advantage plans and many state regulations for commercial plans, insurers must provide the criteria upon request. Understanding what documentation threshold was not met helps you and your doctor craft a targeted appeal.

Tip: Ask your physician to request a peer-to-peer review if the standard appeal process is not succeeding. A direct conversation between your treating physician and the insurer's medical director is often more effective than written appeals, especially for cases where clinical nuance matters.

Tip: Keep copies of all PA request submissions, denial letters, and appeal correspondence. If a PA is approved and later disputed, or if your treatment is delayed and you suffer harm, this documentation is essential for filing complaints with your state insurance department or pursuing further appeals.

Tip: For ongoing treatments, set calendar reminders to track PA expiration dates. Reauthorization requests submitted before the current PA expires prevent gaps in treatment. Many patients experience medication interruptions because neither they nor their provider tracked the expiration date.

Tip: Check whether your state has enacted "gold card" or prior authorization reform legislation. Several states now require insurers to exempt physicians with high approval rates from PA requirements for certain services, and some states have set maximum response time requirements. Knowing your state's rules helps you hold insurers accountable to legal deadlines.

Prior authorization has grown from a targeted review mechanism into a pervasive friction point in healthcare access. While it serves legitimate purposes, the current implementation creates delays, denies appropriate care, and burdens the healthcare system. Understanding how prior auth works helps patients and providers navigate it while policy debates continue about reform.

Sources and Further Reading

• AMA Prior Authorization Physician Survey — American Medical Association (ama-assn.org)
• CMS Interoperability and Prior Authorization Final Rule (CMS-0057-F) — Centers for Medicare & Medicaid Services (cms.gov)
• NAIC Model Prior Authorization Act — National Association of Insurance Commissioners (naic.org)
• Kaiser Family Foundation — Health plan survey data on prior authorization denial rates (kff.org)
• MCG Health (formerly Milliman Care Guidelines) — Clinical criteria documentation (mcg.com)