Newsroom · Sioux Falls

Medicare Prior Authorization Denied? Your Step-by-Step Appeal Guide for 2026

Most denials that get appealed get overturned. Most never get appealed at all.

Big Sioux Benefits Data Desk

Published July 26, 2026 · 12 min read · Sourced from CMS.gov and KFF

If your Medicare Advantage plan just denied a prior authorization request, the single most useful fact to know is this: when people actually appeal, they win more than eight times out of ten. The catch is that barely one in nine denials ever gets appealed. This guide walks through what prior authorization means, exactly how a Medicare appeal works in 2026, and how Sioux Falls-area beneficiaries can build one that has a real shot at succeeding.

Every figure below comes from a public federal or nonpartisan source — KFF's analysis of 2024 CMS prior authorization data, the HHS Office of Inspector General's findings on denial-rate variation, and Medicare.gov's official appeals process. No invented numbers, no "call for details."

What "prior authorization" actually means

Prior authorization is your plan's requirement that it approve a service, test, drug, or piece of equipment before it happens — not after. Your doctor can order an MRI, prescribe a specialty drug, or refer you to inpatient rehabilitation, and your Medicare Advantage plan can still say no before you ever receive the care. That approval sits between your doctor's medical judgment and your plan's payment, and it applies to a genuinely long list of services: advanced imaging, many drugs given by injection or infusion in a clinic, durable medical equipment, inpatient rehabilitation facility stays, skilled nursing facility admissions, and some surgeries.

Most Medicare Advantage plans do not review these requests in-house. They contract with a specialized utilization-management vendor — a company whose entire business is applying clinical criteria to prior authorization requests at scale — and that vendor's own medical policy, not just your doctor's judgment, becomes the standard your request is measured against. CMS's stated rationale for allowing this is straightforward: prior authorization is meant to confirm a service is medically necessary and delivered in the right setting before money changes hands, which in theory protects both the beneficiary and the Medicare Trust Fund from unnecessary care. In practice, the volume of denials that get reversed on appeal is what has drawn regulatory scrutiny — a process meant to filter out unnecessary care is also, demonstrably, filtering out a meaningful amount of necessary care too.

How often denials actually happen

Prior authorization denials are common enough that you should assume they can happen to you, and rare enough that most people are caught off guard the first time. Medicare Advantage insurers submitted 52.8 million prior authorization requests in 2024 — about 1.7 per enrollee — and denied roughly 4.1 million of them, a 7.7% denial rate, up from 6.4% the year before. About 73% of those denials were full denials; the rest were partial.

Source: KFF — Medicare Advantage Prior Authorization Determinations (2024 data).

The variation across insurers is where it gets more striking. An HHS Office of Inspector General review of long-term acute care and inpatient rehabilitation facility prior authorizations found denial rates ranging from about 8% to 80% depending on the company — with UnitedHealthcare, Aetna (CVS Health), and Humana flagged for rates exceeding 70% on some of these stays. Nearly 20 million Medicare Advantage enrollees are covered by the three highest-denying insurers in that review. And when those specific denials were appealed, 95% were overturned.

The overturn rate has stayed above eight in ten for years running — a pattern the HHS Inspector General has called a systemic signal, not an occasional mistake.

The five levels of a Medicare appeal

Every Medicare denial — Original Medicare, Medicare Advantage, or Part D — moves through the same basic ladder, though the names shift slightly by program. Here is the structure that applies to a Medicare Advantage prior authorization denial:

In practice, almost every case that gets resolved favorably resolves at Level 1 or Level 2. Level 3 — a hearing before an Administrative Law Judge at the Office of Medicare Hearings and Appeals — is real, and it is available once the disputed dollar amount clears a CMS-set threshold ($200 for 2026), but OMHA's backlog commonly runs 12 to 24 months. That backlog is exactly why the fight to win early, with strong documentation, matters more than the theoretical right to escalate later.

You do not have to navigate any of this alone. You, your doctor, or someone you formally appoint as your representative (using Medicare's Appointment of Representative form) can file at every level. Level 1 requests can often be started by phone with the plan directly, though CMS recommends following up in writing so there is a dated record. Level 2 requires no action from you at all if your plan denies the Level 1 reconsideration — federal regulation requires the plan to forward the case automatically to the independent reviewer. That single rule is worth remembering: if a plan upholds its own denial, you should never have to re-file from scratch to get an outside, disinterested look at the same facts.

The 2026 decision deadlines that changed

CMS's Interoperability and Prior Authorization Final Rule (CMS-0057-F), finalized in January 2024, put new operational requirements into force on January 1, 2026 for Medicare Advantage plans and several other regulated payers. The headline change: plans must issue a standard prior authorization decision within 7 calendar days and an expedited one within 72 hours — timelines that did not exist in a standardized form before. By January 1, 2027, those same plans must also run a live Prior Authorization API so a provider's office can check requirements and submit a request electronically, part of a broader push toward machine-readable, auditable prior authorization decisions.

The rule also requires plans to give a specific reason for every denial, not a form letter, and to publish their prior authorization approval and denial rates by category. That transparency requirement is precisely the data KFF and the HHS Inspector General have been using to document how much denial rates vary by insurer.

Step therapy and Part D formulary exceptions

Step therapy is prior authorization's cousin on the drug side. Your Part D plan can require you to try — and fail on, or show is medically unsuitable — a lower-cost drug before it will cover the one your doctor actually prescribed. CMS treats a step therapy waiver request the same way it treats a formulary exception: your prescriber submits a supporting statement explaining why the required alternative has been, or is likely to be, less effective for you or would cause adverse effects.

The clock on that request does not start until your plan actually receives the prescriber's supporting statement — so a request that seems to be moving slowly may simply be waiting on paperwork from the clinic, not sitting in the plan's queue. Once the plan has what it needs, it must decide within 72 hours for a standard exception request or 24 hours for an expedited one, whether your life or health could be at risk by waiting.

Building an appeal that actually wins

The 80.7% overturn rate is not luck — it reflects the fact that most denials that get appealed were genuinely appealable, and most appeals that succeed were built the same way. The strongest appeals do one thing consistently: they answer the plan's stated denial reason directly, in the plan's own clinical language, rather than restating why the patient needs the care in general terms. If a denial cites a specific coverage policy or medical criterion, your appeal should reference that exact policy and explain, point by point, why your situation meets it. Here is what to gather before you file:

Success rates differ by service type, which is itself useful information: KFF's data shows 63.9% of appealed durable medical equipment denials succeed, versus 26.3% for ambulance transport and 22.2% for certain hospital outpatient services. A lower success rate for a category does not mean an appeal is not worth filing — it means the documentation needs to work harder.

Original Medicare vs. Medicare Advantage: does switching help?

This is a fair question to ask after a bad prior authorization experience, and the honest answer is that it depends on timing and cost, not just frustration. Original Medicare requires prior authorization for a much shorter list of services, which genuinely reduces this specific friction. But Original Medicare alone leaves a $1,632 Part A deductible per benefit period and an uncapped 20% Part B coinsurance with no annual ceiling unless you pair it with a Medigap supplement — which, outside your one-time guaranteed-issue window, may require medical underwriting in South Dakota. Medicare Advantage plans carry more prior authorization but also carry a built-in annual out-of-pocket maximum that Original Medicare alone does not have.

There is no universal answer, and the tradeoff is exactly why this decision deserves a real comparison rather than a reaction to one bad denial. A single frustrating prior authorization experience is a legitimate reason to review your options at the next enrollment window — it is not, on its own, a reason to assume the opposite path through Medicare would leave you better off financially. Someone managing a chronic condition with frequent imaging or infusion needs may find that a Medigap plan's near-total absence of prior authorization is worth a higher monthly premium. Someone in good health who rarely uses specialty care may find a Medicare Advantage plan's out-of-pocket cap and $0-premium options the better financial trade, prior authorization included. Our full breakdown is in Medigap vs. Medicare Advantage in Sioux Falls.

What this looks like locally: the Sanford & Avera angle

Sioux Falls' Medicare Advantage market runs through five standard PPOs, and every one of them uses prior authorization for at least some imaging, DME, and specialty drug categories — that is a standard feature of Medicare Advantage plan design, not a flaw unique to any single carrier here. What differs locally is which hospital system a denial dispute tends to run through: Sanford USD Medical Center holds a 5-star CMS quality rating and Avera McKennan a 4-star rating, and Sanford's own Align plans naturally route referrals and prior authorization requests through the Sanford network first.

This matters for prior authorization specifically because a plan's utilization-management vendor usually reviews requests against its own clinical criteria, not against which hospital you prefer — so confirming your doctor is in-network is step one, and understanding that plan's specific prior-authorization list for your ongoing conditions is step two. Minnehaha County's CDC-tracked chronic-condition rates make that second step especially relevant: 22.9% of adults have arthritis (driving imaging and injection requests), 10% have diagnosed diabetes (driving CGM and supply requests), and 5.6% have COPD (driving home oxygen and nebulizer requests) — all categories where prior authorization shows up routinely. We break each of those down fully in our durable medical equipment guide and our chronic conditions coverage guide.

Source: CDC PLACES: Local Data for Better Health, County 2023 (2023) & CMS Hospital Compare — Overall Star Ratings.

A worked example: rehab after a hip replacement

Here is how this plays out in a real, common scenario. Someone in Sioux Falls has a hip replacement — a procedure covered under Part A, discussed fully in our hip and knee replacement guide — and their surgeon recommends a short stay at an inpatient rehabilitation facility (IRF) rather than going straight home. The HHS Inspector General's review found some insurers deny IRF prior authorization requests more than 70% of the time, even though the average IRF stay runs about $24,000. If that request is denied and the family simply accepts it, they either pay privately or the patient goes home without the rehabilitation the surgeon recommended.

Source: HHS Office of Inspector General findings, via NBC News.

The math is not subtle: a stay that costs roughly $24,000 if paid privately, against an appeal that costs nothing but time and paperwork and wins 95% of the time in this specific category, is one of the clearest arguments for appealing that exists anywhere in Medicare.

Free help exists — use it

You do not have to build an appeal alone, and none of the help below costs you anything. South Dakota's Senior Health Information and Insurance Education program, SHIINE — the state's federally funded State Health Insurance Assistance Program — offers free, unbiased Medicare counseling, including help understanding a denial letter and preparing an appeal. Reach SHIINE at (866) 854-5465 toll-free or (605) 773-3656 locally.

Big Sioux Benefits can also walk you through how the plans we offer handle prior authorization for your specific drugs and conditions, at no cost — licensed agents are paid by carriers, never by you.

What to watch heading into the 2026 Annual Enrollment Period

1. Check your plan's prior authorization list against your actual ongoing drugs and services before you re-enroll, not after a denial arrives.
2. Read every denial letter fully — the specific reason stated is what your appeal has to answer.
3. Ask for a peer-to-peer review before filing a formal appeal; many denials resolve there.
4. File within the deadline — 65 days for a Medicare Advantage Level 1 reconsideration.
5. Request "expedited" review whenever a delay could genuinely harm your health.
6. Call SHIINE or a licensed local agent before assuming a denial is final — it usually is not.

How we know all this: Big Sioux Benefits runs every article through a data desk that cross-references KFF's national prior authorization research, HHS Office of Inspector General findings, CMS's official appeals-process rules and 2026 dollar thresholds, the CMS-0057-F final rule, and the Minnehaha County CMS plan landscape — built by Strategic AI Architects. Every figure here is sourced; nothing is invented. This is education, not legal or medical advice — confirm your own appeal rights and deadlines with your plan, Medicare.gov, or SHIINE. We take no payment from any carrier to feature a plan.