- A claim appeal is a formal request for a payer to reconsider a denied or short-paid claim, supported by documentation that addresses the exact denial reason.
- The core process has six steps: read the remittance, identify the denial code, gather evidence, write the appeal letter, submit before the deadline, and track the result.
- Most payers offer multiple appeal levels — redetermination, reconsideration, and external/independent review — each with its own deadline.
- Deadlines are strict. Missing a filing window usually forfeits the right to appeal, so calendar every deadline the day the denial posts.
- The fastest way to win appeals is to prevent denials at the source — clean claims, correct authorization, and accurate coding.
Even high-performing practices see a share of claims denied. The difference between losing that revenue and recovering it is a disciplined, repeatable appeal process. Below is the step-by-step workflow our denial management team uses, written so any biller can follow it.
What is a medical claim appeal?
A medical claim appeal is a written request asking an insurance payer to overturn a denial or correct an underpayment. It is different from a corrected claim (used to fix a data error and resubmit) and from a reconsideration (an informal second look). An appeal formally challenges the payer's decision and triggers a defined review process with regulated timelines.
How to appeal a denied claim: 6 steps
Follow these steps in order. Skipping the diagnosis step — understanding exactly why the claim was denied — is the most common reason appeals fail.
- Read the remittance advice (ERA/EOB). Locate the denied line and its adjustment codes.
- Identify the denial reason. Decode the Group Code + CARC/RARC codes to learn the precise problem (missing info, no authorization, medical necessity, etc.).
- Determine if it's appealable. Some denials need a corrected claim instead; confirm the right pathway before writing.
- Gather supporting documentation. Pull the medical record, authorization, referral, operative or progress notes, and any policy language that supports payment.
- Write and submit the appeal letter before the deadline, using the payer's required form or portal.
- Track and follow up. Log the submission date, expected decision window, and escalate to the next level if denied again.
Appeal levels and deadlines
Payers structure appeals in tiers. The names vary, but the escalation path is consistent. Commercial plans, Medicare, and Medicaid each publish their own deadlines — always verify the exact window on the denial notice.
| Level | What it is | Typical filing window |
|---|---|---|
| 1 — Redetermination / First appeal | Initial formal challenge to the payer | Often 90–180 days from denial (commercial); 120 days for Medicare Part B |
| 2 — Reconsideration | Independent review within or contracted by the payer | Commonly 60–180 days from the level-1 decision |
| 3 — External / Independent review | Third-party or administrative-law review | Varies by plan and state; often 60–120 days |
What to include in an appeal letter
A winning appeal letter is short, specific, and tied directly to the denial reason. Include each of these elements:
| Section | What to include |
|---|---|
| Patient & claim identifiers | Patient name, member ID, claim number, date(s) of service, CPT/HCPCS codes |
| Denial reference | The exact CARC/RARC and the payer's stated reason |
| Argument | Why the service was covered, medically necessary, and correctly coded |
| Evidence | Records, notes, authorization, referral, and relevant policy language |
| Request | A clear ask: reprocess and pay the claim, with the expected amount |
Common denial reasons and the fix
Match the denial to the right correction before you appeal. These five drive most denied dollars:
- Missing or invalid information (CARC 16): correct the data element and submit a corrected claim or appeal with the right info.
- No prior authorization (CARC 197): request a retro-authorization or appeal with medical-necessity documentation.
- Not medically necessary (CARC 50): attach clinical notes and the supporting diagnosis linkage.
- Timely filing: appeal with proof of original submission (clearinghouse acknowledgment).
- Coordination of benefits: submit the primary payer's EOB and resubmit to the correct payer.
Keeping these out of your queue starts upstream — a high clean claim rate and low days in A/R mean fewer appeals to write in the first place.
How to prevent denials before they happen
Appeals recover revenue, but prevention protects margin. Build these habits into your denial management program: verify eligibility and benefits before the visit, confirm authorization requirements, scrub claims for coding accuracy, and track denial trends by payer and reason code so you can fix root causes.
Frequently asked questions
Filing windows vary by payer and appeal level. Commercial first-level appeals are often 90–180 days from the denial, while Medicare Part B redetermination allows 120 days. Always confirm the exact deadline printed on the denial notice, because missing it usually forfeits the appeal.
A corrected claim fixes a data or coding error and resubmits the claim for normal processing. An appeal formally challenges the payer's decision on a denied or underpaid claim and triggers a defined review process. Use a corrected claim for errors and an appeal to dispute the payer's determination.
Include patient and claim identifiers, the exact CARC/RARC denial reason, a clear argument for why the service should be paid, supporting documentation (records, authorization, policy language), and a specific request to reprocess and pay the claim.
Most payers offer at least three: a first-level redetermination, a second-level reconsideration or independent review, and an external/independent review. Each level has its own filing deadline and required documentation.
The most common reasons are missing the filing deadline, failing to address the specific denial reason, and submitting insufficient documentation. Decoding the CARC/RARC codes first and tailoring the appeal to that exact reason dramatically improves success rates.
Yes. A denial management partner like VeriMedix decodes denials, gathers documentation, drafts appeal letters, and works each appeal level to deadline, freeing your staff while recovering revenue that would otherwise be written off.