What is the deadline to appeal a claim denial?

Appeal deadlines vary by payer and plan and are often measured from the date on the remittance, commonly anywhere from 60 to 180 days, though Medicare and Medicaid have their own timelines. Missing the deadline usually forfeits the appeal, so check the payer's window immediately.

What should a behavioral health appeal include?

A strong appeal addresses the specific denial reason (CARC) code, includes supporting documentation (clinical notes, medical-necessity justification, authorization records), references the payer's own policy, and is submitted within the deadline using the payer's required appeal process.

What is a peer-to-peer review?

A peer-to-peer review is a conversation between the treating provider and the payer's medical reviewer to argue medical necessity, often used for level-of-care and authorization denials. It can resolve a denial without a formal written appeal.

Denial Management · June 15, 2026 · 6 min read

How to Appeal a Behavioral Health Claim Denial

A denial isn't the end of a claim, it's a step in the process. The problem is that most behavioral health denials are never reworked, so the revenue is simply lost. Here's how to appeal effectively, step by step.

Step 1: Read the denial code

The remittance carries a CARC (claim adjustment reason code) that tells you why the claim was denied, authorization (CO-197), medical necessity (CO-50), timely filing (CO-29), missing info (CO-16), and so on. The code dictates the strategy. (See AI denial management for a code reference.)

Step 2: Confirm the appeal deadline

Appeal windows vary by payer and plan, often 60 to 180 days from the remittance date, with Medicare and Medicaid on their own timelines. Note the deadline the moment you get the denial; missing it usually forfeits the claim.

Step 3: Build the appeal

Address the specific reason. Rebut the exact CARC code, not denials in general.
Attach documentation. Clinical notes, medical-necessity justification, and authorization records.
Cite the payer's policy. Reference the plan's own coverage criteria.
Use the right channel. Submit through the payer's required appeal process and form.

Step 4: Escalate when needed

For medical-necessity and level-of-care denials, request a peer-to-peer review, a direct conversation between your provider and the payer's reviewer. If the first-level appeal fails, most payers offer a second level, and many plans allow an external review.

Better than appealing: preventing

Appeals recover revenue, but the cheaper win is not getting denied in the first place. Verifying eligibility, tracking authorizations, and scrubbing claims up front prevents most denials, and an AI behavioral health billing specialist can both prevent denials and generate corrected claims and appeals automatically. For the common reasons claims bounce, see top reasons behavioral health claims get denied.

For general reference only. Appeal rights, deadlines, and processes vary by payer and plan, verify the specifics for each denial.

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