Can I fax a prior authorization without a fax machine?

Yes. An online fax service sends the packet over the real fax network from your phone or computer. With Just The Fax it is $1.99 for up to 15 pages, with no account and no subscription.

What fax number do I use for a prior authorization?

Use the number printed on the prior authorization form itself, because insurers run separate fax lines for pharmacy prior auth, medical prior auth, urgent review, appeals and claims. If the form has no number, call member services and ask for the prior authorization fax line specifically.

What should I include with a faxed prior authorization?

A cover sheet with patient name, date of birth, member ID, prescriber name and a callback number; the complete signed form; and the clinical justification the form requests, such as chart notes, labs or a letter of medical necessity.

How do I know my prior authorization was received?

Keep the fax delivery confirmation, then call the insurer after two to three business days and ask for the reference or case number. Turnaround clocks generally start on receipt.

How to Fax a Prior Authorization

Prior authorization is the single most-faxed document in American healthcare. Your doctor prescribes something, your insurer wants to approve it first, and the form that decides it moves by fax. If you are the one holding that form, you do not need a fax machine to send it.

Who actually sends it

Usually the prescriber's office handles the clinical form. But patients end up faxing prior auth paperwork constantly, because:

The office says "we sent it" and the insurer says they never got it, so you send it yourself to break the loop.
You are chasing an urgent authorization and cannot wait for a busy office.
Part of the packet is yours: a consent page, a financial assistance application, a copay card enrollment.
The pharmacy needs it and the doctor's office needs it, and somebody has to send the second copy.

None of that requires a machine or a monthly plan.

Getting the fax number right

This is where prior auths die. Insurers run different fax lines for different things -- pharmacy prior auth, medical prior auth, expedited or urgent review, appeals, and general claims are often four or five separate numbers. A correct form sent to the wrong line disappears quietly, and you find out weeks later when the medication still is not approved.

In order of reliability:

The form itself. Prior auth forms nearly always print the destination fax number on the page, and it is department specific. Use that one.
The letter or denial notice, if they contacted you first.
The number on the back of your insurance card. Call member services and ask for the prior authorization fax number *specifically* -- say pharmacy or medical, and say if it is urgent, because those route differently.
The prescriber's office. They fax these daily and often have the current direct line.
Our free fax directory -- verified insurer and pharmacy fax numbers, checked against an official source before they go live. Free, no signup.

Do not reuse a number from an old letter without confirming. Insurers reorganize, merge, and move these lines often.

What goes in the packet

A cover sheet with the patient name, date of birth, member ID, the prescriber's name and NPI if you have it, and a callback number. See what to put on a fax cover sheet or use our free medical template.
The complete form, every page, signed where signatures are required. An unsigned prior auth is a rejected prior auth.
The clinical justification the form asks for -- chart notes, lab results, a letter of medical necessity, or documentation of what you already tried and why it did not work. Step therapy denials usually turn on this.
"URGENT" marked clearly if the prescriber flagged it as expedited. Urgent requests have shorter legal turnaround windows, but only if the insurer knows it is urgent. Our urgent cover sheet has a header that is hard to miss in a stack.

Sending it

Full disclosure: we make Just The Fax. It is a send only online fax service: $1.99 for up to 15 pages, no subscription, no account to create. Longer packets are $2.99 (16-50 pages) or $4.99 (51-100). It exists for exactly this, the person holding one urgent packet who does not want a monthly plan.

Have the signed form and attachments as a PDF, or photograph every page.
Go to justthefax.io/send.
Enter the prior authorization fax number from the form.
Upload the pages and add a free cover sheet with the patient details.
Pay and send. You are only charged if the fax actually delivers.

Your document is deleted the moment the fax finishes. There is no account and we do not keep your paperwork. To be clear about what we are: a general purpose fax service, not a HIPAA Business Associate, and we do not sign BAAs. A patient sending their own paperwork has no such obligation.

After you send

Keep the delivery confirmation. "Transmitted successfully on this date at this time" is what ends the "we never received it" conversation, and prior auth turnaround clocks usually start on receipt.
Call in 2-3 business days and ask for the reference or case number. Once you have that, you can check status without re-faxing anything.
If it is denied, the denial letter contains your appeal rights and the appeals fax number. See how to fax an insurance appeal.

Related guides

How to fax an insurance appeal - the next step when a prior auth comes back denied.
How to fax a specialty pharmacy - when the medication is specialty and the pharmacy needs a copy too.
How to fax medical records - sending the chart notes that support the request.
How to fax an insurance company - the general playbook for reaching any insurer.

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