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Home > Guides > Faxing a prior authorization request
Yes, many insurers still accept prior authorization requests by fax, and for some plans fax is the main intake channel for these forms. Include the patient and provider details, the exact service or drug, the diagnosis code, and supporting clinical notes, then track the decision by the reference number on your confirmation page and a follow-up call.
Prior authorization is an insurer requirement that certain treatments, procedures, or drugs be approved before they are provided, so the insurer can check medical necessity and coverage. The request usually travels from a clinic or pharmacy to the insurer, and fax remains common because clinics already have fax workflows and insurers have fax intake queues tied to their approval systems. Portals exist for many plans, but smaller practices and urgent requests still go by fax, and some insurers publish a fax number specifically for prior authorization forms.
The stakes are practical: without approval, the insurer may refuse to pay, leaving the patient with the bill or delaying care. That is why the request packet matters more than the sending method. An incomplete packet gets denied or bounced back for more information, and each round trip adds days. Sending a complete packet the first time is the single best way to shorten the wait.
Use the insurer form for that plan, not a generic letter, since plan forms ask for the exact fields their reviewers check. Include the patient full name, date of birth, and member ID; the provider name, practice address, and contact number; the requested service or drug with dosage and quantity where relevant; the diagnosis code; and the clinical notes that justify the request, such as prior treatments tried and their outcomes. Add a cover sheet with the member ID and a callback number, but keep sensitive details off the cover sheet itself.
One non-obvious point: the diagnosis code and the service code must match. Reviewers deny requests where the code pair does not support the service, even when the clinical notes make sense to a human reader. If a request is denied for a coding reason, the fix is usually a corrected code, not a longer letter. Also note the date of service if the form asks for it: an authorization is often valid only for a window around that date, and a request sent too early or too late can be denied on timing alone.
| Packet item | Why reviewers need it |
|---|---|
| Insurer prior auth form | Plan-specific fields their system checks first. |
| Patient and member ID | Matches the request to the right coverage. |
| Provider details | Confirms who is requesting and where to reply. |
| Service or drug details | Defines exactly what approval covers. |
| Diagnosis code | Must support the requested service. |
| Clinical notes | Shows medical necessity and prior treatments tried. |
Keep the confirmation page and note the date, the fax number, and the member ID. Many insurers give a reference or case number in their reply, and that number is the key to every follow-up call: without it, staff must search by member ID and date, which takes longer. If no reply arrives within the window the plan states, call and ask for the status by reference number, and ask whether more information is needed rather than simply waiting. For urgent requests, ask the clinic to mark the request urgent on the form and to note the clinical reason, since urgent queues are handled separately at many insurers.
If the request is denied, ask for the denial reason in writing. A denial for missing information can be fixed with a corrected fax, while a denial on medical-necessity grounds usually needs an appeal with additional clinical evidence. Keep every page: the original request, the confirmation, the denial, and the appeal form a record that matters if the decision is challenged.
Yes, for US and Canadian insurer fax numbers. You ask your AI assistant, get a per-fax quote with the page count verified, approve the exact total, and pay once through Stripe. Fax is currently in testing, so it is described as available in testing and a fax is never promised to send on a particular day. Verify the insurer fax number from the plan documents before approving, and keep the confirmation page as your tracking record.
Ready to fax it? Fax with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it is sent.
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