How fast to answer a prior authorization request for more information

Answer a plan's request for more information inside the window printed on it, because that window sits inside the plan's own decision clock, which for Medicare Advantage, Medicaid and CHIP keeps running while the plan waits (CMS-0057-F). No federal rule gives the prescriber a deadline of its own, and the fax transmission report shows when the answer arrived.

Does the prior authorization clock stop when the plan asks for more information?

The prior authorization clock keeps running for Medicare Advantage, Medicaid and CHIP when the payer asks for documentation it did not disclose with the original request, although the payer may extend where its program allows (CMS FAQ). CMS says the payer must ask in time for the provider to supplement the request, so the decision and notice still land inside the deadline.

The extensions are limited. A Medicare Advantage plan may extend a standard decision by up to 14 calendar days on stated grounds, one of which is that the extension is justified and in the enrollee's interest because the plan needs additional medical evidence from a noncontract provider that may change its decision to deny (42 CFR 422.568). A Medicaid managed care plan may extend by up to 14 additional calendar days if the enrollee or the provider asks, or if the plan justifies a need for additional information and how the extension is in the enrollee's interest (42 CFR 438.210).

CMS-0057-F times prior authorization for medical items and services only, so its clocks leave out drug requests and the qualified health plan issuers on the federal exchanges. A Part D exception request is timed from the prescriber's supporting statement: if none arrives within 14 calendar days of the request, the 72 hours run from the end of those 14 days (42 CFR 423.568). For Part D, CMS allows tolling of the start of the clock only when the request is at the coverage determination level, involves an exception, has no supporting statement yet, and is a request for benefits (not reimbursement), and once a written statement is in, additional tolling is not permitted.

A group health plan that gets an incomplete urgent claim must name the missing items within 24 hours, give the claimant at least 48 hours to supply them, and decide within 48 hours of the earlier of the information or the end of that period (29 CFR 2560.503-1).

How long do you have to answer a request for more information?

No federal rule gives the prescriber a deadline of its own for answering a plan's request for more information; the window printed on the request, such as 24 hours, 48 hours or 3 days, is the plan's reply window inside its own decision clock. Answer inside that window, because the plan's clock keeps running.

The group health plan rule sets minimums the plan must allow the claimant: at least 48 hours to supply what an incomplete urgent claim lacks, and at least 45 days from receipt of an extension notice to provide the information it names for a pre-service claim. New York's insurance regulator gives the same 24 and 48 hour pattern for an urgent step therapy override request that arrives without its supporting rationale: the plan requests the information within 24 hours, and the insured and the health care professional have 48 hours to submit it (New York Department of Financial Services).

What does the plan's request ask for, and what do you send back?

A plan's request for more information names the missing items, and the answer is everything the request names, sent back in one fax. For a Part D exception, CMS has developed a model Request for Additional Information form that a plan sponsor may use to ask for a supporting statement, additional information, or both.

The prescriber's supporting statement is any statement, verbal or written, that indicates the drug is medically necessary, and it does not have to be complete to count as received and start the timeframe. If the plan still needs more after the written statement, it must obtain it and decide within 24 hours for an expedited request or 72 hours for a standard one, counted from the written statement (CMS Parts C and D guidance).

For an expedited Part D exception request the 24 hours run from receipt of the prescriber's supporting statement (42 CFR 423.572).

What happens if you don't answer?

A Medicare Advantage or Part D plan that gets no answer decides on what it has: CMS says that if a plan does not receive any additional information it should make the best decision it can based on the information available, within the required adjudication timeframes.

CMS says plans with too little information to approve a request should make reasonable and diligent efforts to obtain it, says one outreach attempt is enough, and names telephone, fax and e-mail among the methods a plan may use. If a plan denies because it could not get needed clinical information, CMS says the written denial notice should name that basis and the information needed. The prescriber can then appeal or resubmit with the missing items.

In WISeR, CMS's Original Medicare model in six states, a non-affirmation lists everything missing or noncompliant with instructions for resubmission, and the request can be resubmitted without limit (WISeR provider guide).

How do you send the answer and prove it arrived in time?

The answer goes back to the number or channel the plan's request names, and the fax transmission report goes in the file, because CMS counts a faxed answer as received by a Medicare Advantage or Part D plan once that report shows a successful transmission. For Part D the same rule dates the prescriber's supporting statement for an exception request.

A delivery record shows when the pages reached the plan's line, and how to tell if a fax went through covers reading one. As a matter of practice, every original request should carry a contact and a fax number that someone in the office watches, because CMS lists portal, fax, email, mail and phone as channels a decision may use and links none of them to the number on the form.

Which clocks apply at Part D, Medicare Advantage, Medicaid and employer plans?

Part D plans decide in 72 hours (24 expedited), Medicare Advantage plans in 7 calendar days for items and services and 72 hours for a Part B drug, Medicaid managed care plans in 7 calendar days, and a group health plan in 15 days for a pre-service claim or 72 hours when the claim is urgent.

The table sets out each program's clocks and what a request for more information does to them.

The full clock tables are in how to fax a prior authorization request and how to request an expedited prior authorization. A Medicare ADR is a different request for more information, with its own clock (how to respond to a Medicare ADR by fax).

How do you receive prior authorization requests and decisions securely by fax?

A practice receives a plan's requests for more information and its decisions securely on its own fax number, at a HIPAA fax service that signs a BAA and lets more than one person see each request before its window closes. Fax Pigeon signs a BAA at signup on every plan and gives every paid plan the practice's own number, so a plan's request for more information and its decision can arrive by fax. In the shared inbox with roles and assignment, each request goes to the person who owns the prior authorization, and the answer goes back from the browser or from email with an optional cover sheet and delivery proof on every delivered fax.

* Official sources (CMS, the eCFR, the New York Department of Financial Services) were read on October 26, 2026. Fax Pigeon prices and plan terms as of October 26, 2026.