Prior authorization denied by fax? Peer-to-peer, resubmit or appeal

When a prior authorization decision arrives by fax, read it for the path it opens: a denial must state the specific reason and what to send, a peer-to-peer runs on the plan's own clock, and a Medicare Part D redetermination or Medicare Advantage reconsideration must be requested within 65 calendar days from the date of the notice.

What do you do when a prior authorization decision arrives by fax?

A faxed prior authorization decision takes five steps: name the decision, find its reason, choose the path, file inside the window and keep the delivery record.

1. Read which decision it is: an approval with conditions, a denial, or a request dismissed or decided on missing information.
2. Find the reason and what is missing; a Medicare denial notice must state the specific reason.
3. Choose the path: resubmit with what was missing, ask for a peer-to-peer where the plan offers one, or file a redetermination or reconsideration.
4. File inside the window the notice opens.
5. Keep the delivery record of what you sent beside the plan's reference number.

Each decision brings its own notice, next step and window, set by the rule or the plan named in the last column.

What does an approval notice tell you?

A Part D approval notice tells the prescriber and the enrollee the conditions of the approval, and 42 CFR 423.568 requires those conditions in a readable and understandable form. When a prescriber filed the request, the plan must notify the prescriber and send the enrollee written notice. A granted Part D exception covers refills and new prescriptions for the rest of the plan year, so long as the enrollee stays enrolled, the prescriber goes on prescribing the drug and the drug remains safe for the condition.

What must a denial notice say?

A Medicare denial notice must state the specific reason for the denial: Part D plans use Form CMS-10146, the Notice of Denial of Medicare Prescription Drug Coverage, and Medicare Advantage plans use the Integrated Denial Notice, Form CMS-10003-NDMCP.

The Part D notice's reason takes into account the enrollee's medical condition, disabilities and language needs, and for a drug that could be approved as an exception it must ask for a prescriber's supporting statement and name the information to submit. The Integrated Denial Notice explains why the services, items or Part B drugs were denied, with the coverage rule or plan policy, under CMS's Parts C and D appeals guidance.

Beginning in 2026, the CMS-0057-F rule requires impacted payers to give a specific reason for a denied prior authorization, however the request was sent, except for drugs. Medicaid fee-for-service carries the same duty from January 1, 2026 under 42 CFR 431.80. An employer group health plan under 29 CFR 2560.503-1 must give the specific reasons and describe any material needed to complete the claim.

Wellmark's Medicare Advantage manual lets a provider who disagrees with a Part D decision ask CVS Caremark for a free copy of the criteria or guidelines used.

What happens when a request is closed for missing information?

A Medicare plan missing information needs only one outreach attempt, by telephone, fax or e-mail, before it decides on what it has within the required timeframe, and it may dismiss a request only for a reason the rules list.

A plan that dismisses a request must send written notice to the parties' last known address by the end of the adjudication timeframe, and review of the dismissal must be requested within 65 calendar days from the date of that notice. A standard exception request without the prescriber's supporting statement waits at most 14 calendar days, and the plan then decides within 72 hours from the end of those days.

For the payers and items CMS-0057-F covers, the clock does not stop or restart when the payer asks for more documentation. Optum Rx says an incomplete request may result in a denial unless all required information is received, and Express Scripts says nearly all coverage reviews finish within two days of receiving complete information from the doctor.

When should you ask for a peer-to-peer review?

A peer-to-peer review must be requested inside the plan's own window, and UnitedHealthcare says most of its reviews need a request within 24 hours of the coverage denial, though the window varies by plan and state.

UnitedHealthcare describes a peer-to-peer as a discussion where a provider can learn more about a denial of coverage for inpatient and outpatient services, and one can come before an appeal. The service covers prior authorizations UnitedHealthcare manages itself, and reviews run by third-party vendors sit outside it. Inpatient cases must be submitted within 3 business days and outpatient cases within 21 calendar days from the posted denial.

Wellcare's 2026 Medicare Advantage manual says its determination, given verbally or by facsimile, includes the contact for requesting a peer-to-peer, and Wellcare answers a request within two business days. Wellmark makes the peer-to-peer part of a pre-service appeal, with the appeal form sent preferably by fax and some available dates and times for the call. CMS guidance says a Medicare plan should not use a peer-to-peer to push a prescriber into changing a pending request.

How long do you have to ask for a redetermination or reconsideration?

A Medicare Part D redetermination or a Medicare Advantage reconsideration must be requested within 65 calendar days from the date of the notice.

For a Part D redetermination, the enrollee, the prescriber or the enrollee's representative may appeal, and a prescriber may file a standard request after giving the enrollee notice. A standard request goes in writing unless the plan accepts verbal ones, and an expedited request may be verbal or written. The plan decides within 7 calendar days, or 72 hours when expedited, and cannot hold an exception request while it waits for the supporting statement.

For a Medicare Advantage reconsideration, a treating physician may request a standard pre-service reconsideration after giving the enrollee notice, and the plan must expedite one a physician asks to expedite. Decisions take up to 30 calendar days pre-service, 7 calendar days for a Part B drug and 72 hours when expedited.

Employer group health plans allow at least 180 days to appeal and decide an urgent care appeal within 72 hours. Wellmark's manual gives 65 calendar days from the date of CVS Caremark's first decision to dispute a Part D coverage determination. The fax lines for the next step are on their own pages: the Medicare Part D reconsideration fax number, UnitedHealthcare's provider appeals fax number and Aetna's provider appeals fax number.

Why do plans send decisions by fax, and what if yours misses one?

Some plans send prior authorization decisions by fax because their manuals name fax as a notice channel: Wellmark's manual says CVS Caremark notifies the provider of a Part D decision by fax, and Wellcare notifies providers verbally or by facsimile.

Wellcare also faxes a follow-up Drug Utilization Review form stating why a Part D coverage determination request was not approved. A Part D plan that reaches the prescriber by phone owes the prescriber no written follow-up, though the enrollee still gets written notice.

A fax line that misses a decision can miss the notice whose date starts the 65 calendar days, or the one outreach attempt a plan may make for missing information. On Fax Pigeon, incoming faxes land in a shared inbox with roles and assignment with an AI summary of each. Every delivered fax gets delivery proof, and the BAA is signed at signup.

* Fax Pigeon prices and plan terms as of October 20, 2026. Outside sources were read on October 20, 2026.