We once sat with a payer's appeals supervisor who described her team's day: a queue of several hundred letters, a few minutes each, and a checklist of six items. Is the claim identified? Is the denial reason identified? Does the letter say what the provider wants? Does it cite a policy or rule? Is the evidence attached and labeled? Is it within the deadline? A letter that passed all six went to a clinical reviewer or got reprocessed. A letter that missed any of them got a form letter restating the denial. She estimated most of what crossed her desk missed at least two.
That conversation changed how we write appeals. The reader is not a judge weighing a narrative. The reader is a person with four minutes who needs to find six facts fast. The structure below exists to make those six facts impossible to miss, and to keep the clinical or contractual argument short enough that the reviewer actually reads it.
A claim appeal that gets read, then, is one page plus attachments. It identifies the claim and the patient in a header block, names the denial code and the payer's stated reason in the first sentence, states what you are asking for in the second, makes a specific argument that cites the rule the payer itself uses, lists the attached evidence by exhibit number, and arrives before the deadline through a channel that produces a receipt. The rest of this article walks through that structure, shows a full sample, explains each part, and then adapts it to the denial types that make up most of the appeals an independent practice files.
Before you write: is this an appeal at all?
A surprising share of "appeals" should never be written, because the denial calls for something else. Three cases come up constantly.
First, a correction. If the claim had a wrong diagnosis pointer, a missing modifier, a wrong place of service or a typo in the member ID, the fix is a corrected claim (frequency code 7 in the 837P CLM05-3, or resubmission code 7 in box 22 of the CMS-1500 with the original claim number), not an appeal. Appealing a claim that needs correction wastes the appeal and the deadline. For Medicare, minor clerical errors go through the reopening process, which the Medicare Administrative Contractor can handle by phone or in writing, rather than through redetermination.
Second, a reconsideration. Many commercial payers and most Medicaid managed care plans distinguish between a "claim reconsideration" (a re-review of a processing error, often by phone or a simple form) and a formal appeal with clinical review. Use the reconsideration for payer errors such as a claim denied for no authorization when one exists, or paid at the wrong fee schedule. Save the appeal for disputes about coverage, medical necessity or coding judgment.
Third, a member appeal filed on the patient's behalf. For Medicare Advantage pre-service denials and many commercial medical necessity denials, the strongest route is the member's appeal rights, exercised with the patient's written appointment of representative (form CMS-1696 for Medicare). Member appeals carry statutory timeframes and independent external review; provider contractual appeals often do not.
The structure of an appeal letter
- Header block. Your letterhead; date; the payer's appeals address exactly as the denial letter or provider manual states it; a reference line with patient name, member ID, claim number (the payer's ICN or DCN), date of service, billed amount and the denial code with its description.
- Opening paragraph: request and reason. One or two sentences. "We are appealing the denial of claim [number] for [service] on [date], denied with reason code [CARC] ([payer's wording]). We request that the claim be reprocessed and paid at the contracted rate."
- Facts. Three to five sentences. Who the patient is in clinical terms (age, relevant diagnoses with ICD-10-CM codes), what was done (CPT or HCPCS codes, units, modifiers), and the relevant history.
- Argument. The core. Name the rule the payer applies, then show point by point that the claim meets it. Quote the payer's own medical policy number and criteria, the applicable LCD or NCD, the CPT guidelines, the NCCI edit, the contract clause, or the timely filing provision, as the denial type requires. Each point ends with a pointer to the exhibit that proves it.
- Enclosures. A numbered list of exhibits, each labeled on the document itself.
- Close. The remedy again, a contact name and direct phone, and a sentence reserving the next level of appeal.
- Signature. The treating provider for medical necessity and coding appeals; the billing manager or practice administrator for administrative appeals.
A full sample appeal letter
The patient, provider and payer below are fictional. The format is the one we use.
Westside Family Medicine, P.C.
1200 Example Avenue, Suite 210, Springfield
[Date]
Appeals Department
Example Health Plan
P.O. Box 0000, Anytown
RE: First-level provider appeal
Patient: [Patient name] Member ID: [ID] Date of birth: [DOB]
Claim number: [Payer ICN] Date of service: [DOS] Billed amount: $412.00
Rendering provider: [Name], NPI [Type 1 NPI] Billing provider: Westside Family Medicine, P.C., NPI [Type 2 NPI], TIN [TIN]
Denial: CARC 50, "These are non-covered services because this is not deemed a medical necessity by the payer", with RARC N115 referencing Medical Policy MP-0417
To the Appeals Department:
We are appealing the denial of CPT 93000 (electrocardiogram with interpretation and report) and CPT 99214 (established patient office visit, moderate complexity) on the date of service above, denied as not medically necessary under Medical Policy MP-0417. We request that both lines be reprocessed and paid at the contracted rate.
The patient is a 62-year-old established patient with hypertension (I10) and type 2 diabetes without complications (E11.9) who presented with three days of intermittent chest pressure on exertion (R07.9). Dr. [Name] performed a detailed history and examination, ordered and interpreted a 12-lead electrocardiogram in the office, adjusted the patient's antihypertensive regimen and arranged urgent cardiology follow-up. The visit note and the ECG tracing with interpretation are attached.
Medical Policy MP-0417, Section II.A, states that a resting electrocardiogram is medically necessary "for evaluation of a patient presenting with chest pain, chest pressure or other symptoms suggestive of cardiac ischemia" (Exhibit 2). The patient presented with exertional chest pressure, documented in the history of present illness (Exhibit 1, page 1), which falls squarely within that criterion. The diagnosis code R07.9 reported on the claim is listed in the policy's covered diagnosis table (Exhibit 2, page 4). The ECG was interpreted by the ordering physician on the same date and the interpretation is in the note (Exhibit 1, page 3), satisfying the policy's documentation requirement in Section IV. The office visit was separately identifiable from the ECG and was reported with modifier 25 in accordance with CPT guidance; the medical decision making documented (new problem with uncertain prognosis, prescription drug management) supports the moderate complexity level billed.
Enclosures:
Exhibit 1: Progress note for [DOS], 3 pages, signed by [Name], M.D.
Exhibit 2: Example Health Plan Medical Policy MP-0417, current version, with Section II.A and the covered diagnosis table highlighted, 6 pages
Exhibit 3: 12-lead ECG tracing with physician interpretation, 1 page
Exhibit 4: Remittance advice showing the denial, 1 page
Exhibit 5: Copy of the original claim (CMS-1500 image), 1 page
We ask that the claim be reprocessed and paid in full. If the plan maintains the denial, please provide the name and specialty of the reviewing clinician and the specific criterion in MP-0417 the plan believes was not met, and treat this letter as our request for a peer-to-peer discussion. We reserve the right to proceed to the second level of appeal and, where available, to external review.
Please direct questions to [Billing manager name] at [direct phone] or [email].
Sincerely,
[Name], M.D.
Westside Family Medicine, P.C.
What each part is doing
The reference block
Every identifier the payer could use to find the claim, on one block, at the top. The claim number is the payer's number from the remittance, not your internal account number. Both NPIs and the TIN matter because many payers index appeals by billing provider, and a mismatch sends the letter to the wrong queue. Writing out the denial code with the payer's exact wording tells the reviewer you read the remittance.
The opening paragraph
Request first, in the first sentence. Reviewers told us the single most common failure is a letter that never states what the provider wants: reprocess, pay, overturn an authorization denial, apply a different fee schedule. Say it, and say it in terms the payer can act on.
The facts paragraph
Clinical enough to be credible, short enough to be read. Every diagnosis and procedure appears with its code, because the reviewer is comparing the letter to the claim and to a policy organized by code. Do not narrate the whole encounter; the note is attached for that.
The argument
Notice what the argument does not do. It does not say the service was "clearly necessary" or that the physician "used her clinical judgment". It quotes the payer's own criterion and points to the page in the record where it is met. One criterion, one sentence, one exhibit pointer. When a denial involves two lines with two issues (medical necessity on one, modifier 25 on the other), each gets its own sentence with its own authority. This is the part that moves a reviewer, and the part most letters replace with adjectives.
The enclosures
Numbered, labeled, page counts stated. Highlight the relevant passages in the policy and the note. Attach the remittance and the claim image so the reviewer does not have to pull them. Attach only what the argument cites; a 40-page chart dump signals that you did not know what mattered.
The close
The remedy repeated, a specific request for the reviewer's name and specialty and the unmet criterion if the denial stands (many state laws and Medicare Advantage rules entitle you to this, and the request itself prompts a more careful review), the peer-to-peer request, and the reservation of further appeal rights so the letter cannot be treated as the end of the matter. A direct phone number for a person who knows the case shortens everything.
Variations by denial type
| Denial type (typical codes) | The rule to cite | Evidence to attach | What changes in the letter |
|---|---|---|---|
| Medical necessity (CO-50, CO-56, N115) | Payer medical policy by number and section; Medicare LCD or NCD; specialty society guideline if the policy references it | Note, test results, prior treatment history, the policy with criteria highlighted | Treating provider signs; criteria matched point by point as in the sample |
| Prior authorization absent (CO-197, CO-15) | The approval itself, or the payer's retro-authorization and emergency provisions in the provider manual | Authorization letter or portal screen with number, codes and dates; call reference numbers; eligibility response | Administrative signer; if authorization existed, the letter is one paragraph plus the proof; if not, explain the circumstances and argue the service met criteria |
| Timely filing (CO-29) | Contract filing limit and its exceptions: proof of timely submission, retroactive eligibility, other payer's denial date, payer error | Clearinghouse acceptance report (999 and 277CA) with dates, prior payer's remittance, eligibility history | Administrative signer; the whole argument is the dated evidence, so lead with the acceptance report |
| Bundling and NCCI (CO-97, CO-234, M80, N19) | The NCCI Policy Manual chapter for the code pair and the modifier indicator; CPT guidance on separate procedures | Note showing separate site, session or encounter; operative report; the NCCI table row | Coder or provider signs; explain why the modifier (59, XS, XE, XU, 25) applies, with the documentation line that proves it |
| Level of service downcoded (CO-150, N432 after review) | CPT E/M guidelines in force on the date of service (medical decision making or time); payer's E/M policy | Note with the MDM elements marked; time statement if time was used; problem list and orders | Provider signs; walk the three MDM elements and show two of three meet the level billed |
| Not covered or benefit exclusion (CO-96, CO-204) | The patient's plan document or evidence of coverage; state mandated benefit laws where applicable | Benefit verification, plan document page, eligibility response | Often a member appeal filed with the patient's appointment of representative; if truly excluded, bill the patient per your financial policy instead of appealing |
| Medicare redetermination (any Part B denial) | The Medicare Benefit Policy Manual or Claims Processing Manual chapter, the LCD or NCD, and the Medicare Claims Processing Manual Chapter 29 for procedure | Everything above as applicable, plus form CMS-20027 or a letter containing its required elements | Must include beneficiary name, Medicare number, specific services and dates, the requesting party's name and signature, and the reason you disagree |
For the timely filing case, one practitioner opinion: do not appeal a timely filing denial unless you have dated proof. Payers are rarely moved by circumstances, and the deadline for the appeal itself is running. Spend the time instead on the tracking system that stops the next one; our denial code lookup lists the standard evidence for CO-29 and the exceptions each payer type recognizes.
Deadlines and levels by payer type
The deadline is on the remittance or the denial letter, and it is the first thing to write on the appeal record. The governing document is always the payer's provider manual or the plan's evidence of coverage, and thresholds that change each year (such as the Medicare amount in controversy for a hearing) should be checked on the CMS appeals pages when you file.
| Payer type | First level | Deadline to file | Payer decision time | Next levels |
|---|---|---|---|---|
| Original Medicare Part B | Redetermination by the Medicare Administrative Contractor (form CMS-20027 or letter) | 120 days from receipt of the initial determination | 60 days | Reconsideration by the Qualified Independent Contractor (180 days to file, 60 days to decide); hearing with the Office of Medicare Hearings and Appeals (60 days to file, minimum amount in controversy, adjusted annually); Medicare Appeals Council; federal district court |
| Medicare Advantage (contracted provider, post-service) | Plan's provider payment dispute or appeal process per the contract | Set by contract, often 60 to 180 days | Set by contract, commonly 30 to 60 days | Second-level plan review; some plans offer arbitration. Non-contracted providers may appeal payment denials through the member appeal process with a waiver of liability |
| Medicare Advantage (pre-service, member appeal) | Reconsideration of the organization determination | 60 days from the notice | Standard pre-service 7 calendar days under CMS-0057-F; expedited 72 hours; payment denials 60 days | Automatic forwarding to the Part C Independent Review Entity if the plan upholds; then ALJ, Council, court |
| Medicaid managed care | Provider appeal or claim dispute per the plan's provider manual, within state rules | Commonly 60 to 180 days; set by state and contract | Set by state and contract | State fair hearing (member) or the state's provider complaint process |
| Commercial, fully insured (state regulated) | Provider appeal per contract; member internal appeal under the Affordable Care Act rules | Provider: per contract, often 60 to 180 days. Member: 180 days from the denial notice | Member internal appeal: 30 days pre-service, 60 days post-service, 72 hours urgent | Second internal level where offered; state external review; state insurance department complaint |
| Commercial, self-funded (ERISA) | Provider appeal per contract; member internal appeal under the Department of Labor claims procedure rules | Provider: per contract. Member: 180 days | Member: 30 days pre-service, 60 days post-service, 72 hours urgent, one extension in limited cases | External review by an independent review organization; federal court. State insurance laws generally do not apply |
Send the appeal through a channel that produces a receipt: the payer's portal with a confirmation number, fax with a transmission report, or certified mail. Log the date sent, the channel, the confirmation and the date a decision is due. If that date passes with no response, call, get a reference number, then escalate in writing. Practices that keep this log also learn which payers ignore first-level appeals and should be taken straight to the second level or the state regulator.
Questions we hear
How long should an appeal letter be?
One page for the letter, as many pages as the evidence needs for the attachments. If the argument does not fit on a page, it usually has not been reduced to the criteria. Multi-line claims with different denial reasons can run to a second page, with a heading for each line.
Who should sign the appeal?
The treating provider signs anything that argues medical necessity or the level of service, because the reviewer is a clinician and the argument is clinical. The billing manager or administrator signs administrative appeals about authorization, timely filing or payment amount. Either way, the letter names a contact who can answer the phone.
Should we appeal every denial?
No. Appeal denials where the claim was right and the payer was wrong, and denials where the record supports the service and the amount justifies the time. Correct claims that were wrong. Write off denials that were legitimately not payable (an excluded benefit, a service without coverage criteria met) and fix the process that produced them. A denial log sorted by reason and dollars is how you decide; our denial management service makes that triage daily for the practices we support, and the appeal rate that results is lower than most practices expect, with a higher share overturned.
What is the success rate of claim appeals?
It depends on the payer, the denial type and the quality of the appeal, so we do not quote a number. Two facts are worth knowing. The HHS Office of Inspector General found in a 2018 review that Medicare Advantage plans overturned about three quarters of their own denials when enrollees and providers appealed between 2014 and 2016, which tells you that a large share of denials are not final decisions. And a well-documented first-level appeal that cites the payer's own criteria is overturned far more often than a form letter, which is the only part you control.
Can we appeal a denial that has already passed the appeal deadline?
Payers generally will not accept a late appeal, though some recognize good cause (a disaster, a payer system outage, wrong appeal instructions on the denial), and Medicare allows a late redetermination request when good cause is shown and explained. If the appeal deadline is lost, check whether the claim can still be corrected and resubmitted within the timely filing limit, and whether a member appeal with a different clock is available.
Do we need the patient's permission to appeal?
Not for a provider appeal under your contract; the claim is yours. For a member appeal filed on the patient's behalf (common for pre-service Medicare Advantage denials and for benefit disputes), you need the patient's written appointment of representative, which for Medicare is form CMS-1696 and for commercial plans is usually the plan's own authorized representative form. Keep the signed form with the appeal record.
Sources and references
- Original Medicare (Fee-for-service) Appeals, CMS: the five levels of Part A and Part B appeals and the links to each level's rules.
- First Level of Appeal: Redetermination by a Medicare Contractor, CMS: the 120-day filing deadline, the 60-day decision time, form CMS-20027 and the required contents of a written request.
- Medicare Managed Care Appeals & Grievances, CMS: Medicare Advantage organization determinations, reconsiderations, expedited timeframes and the independent review entity.
- Internal appeals, HealthCare.gov (HHS): the member internal appeal rights for commercial plans, including the 180-day filing window and the 30-day and 60-day decision timeframes.
- Claim Adjustment Reason Codes, X12: the official CARC list used to identify the denial reason you are appealing.
- Remittance Advice Remark Codes, X12: the official RARC list that supplies the detail behind a CARC on the remittance.
- Medicare Claims Processing Manual (Publication 100-04), CMS: the manual whose Chapter 29 sets out Medicare appeal procedures, and whose other chapters supply the billing rules cited in appeals.
