Medical Claim Appeal Letter Templates by Denial Code (2026)

Copy letter[Practice name] [Practice address] [NPI / Tax ID] [Date] [Payer name], Appeals Department [Payer appeals address or fax] RE: Appeal of claim denial Patient: [Patient name] Member ID: [Member ID] Date of birth: [DOB] Claim number: [Claim number] Date of service: [DOS] Provider: [Rendering provider name, NPI] Billed amount: [$ amount] Denial reason code: [CARC/RARC] Dear Appeals Reviewer, We are appealing the denial of the above claim under reason code CO-29 (time limit for filing has expired). The claim was submitted within your timely filing limit, and the enclosed documentation proves receipt. Our records show the claim was first submitted on [original submission date] through [clearinghouse name] and accepted by [Payer] on [277CA acceptance date], which is [number] days after the date of service and within your [X]-day filing limit. The enclosed 277CA acknowledgement carries your claim control number [payer ICN]. [If applicable: The delay was outside our control because (choose one): the member's coverage was added retroactively on [date], after the date of service; the claim was first billed to [primary payer], whose remittance dated [date] is enclosed, and this claim was filed within [X] days of that remittance; your organisation returned the original claim in error on [date] for [reason], which was corrected and resubmitted on [date].] We request that the denial be reversed and the claim processed for payment of [$ amount]. Please contact [contact name, phone, email] with any questions. Sincerely, [Name, title] [Practice name] Enclosures: [list]

Copy letter[Practice name] [Practice address] [NPI / Tax ID] [Date] [Payer name], Appeals Department [Payer appeals address or fax] RE: Appeal of claim denial Patient: [Patient name] Member ID: [Member ID] Date of birth: [DOB] Claim number: [Claim number] Date of service: [DOS] Provider: [Rendering provider name, NPI] Billed amount: [$ amount] Denial reason code: [CARC/RARC] Dear Appeals Reviewer, We are appealing the denial of the above claim under reason code [CO-197 / CO-15] (precertification/authorization absent or invalid). [Option A, authorization existed:] Authorization [number] was approved by [Payer] on [date] for [service/CPT codes] with valid dates [from] to [to], covering the date of service. The number was [omitted from / entered incorrectly on] the original claim. A corrected claim (frequency code 7) with the authorization number is enclosed. [Option B, retroactive authorization requested:] The service was rendered on an [urgent / emergent] basis, as documented in the enclosed clinical notes, and authorization could not be obtained before the service without risk to the patient. We request retroactive authorization under your policy [policy name or number, if known] and reprocessing of the claim. [Option C, authorization not required:] Under your [year] provider manual, section [X], [CPT code] does not require prior authorization for [in-network providers / this place of service]. A copy of the relevant page is enclosed. We request reversal of the denial and payment of [$ amount]. Please contact [contact name, phone, email] with any questions. Sincerely, [Name, title] Enclosures: [list]

Copy letter[Practice name] [Practice address] [NPI / Tax ID] [Date] [Payer name], Appeals Department [Payer appeals address or fax] RE: Appeal of claim denial Patient: [Patient name] Member ID: [Member ID] Date of birth: [DOB] Claim number: [Claim number] Date of service: [DOS] Provider: [Rendering provider name, NPI] Billed amount: [$ amount] Denial reason code: [CARC/RARC] Dear Appeals Reviewer, We are appealing the denial of the above claim under reason code CO-50 (not deemed a medical necessity). The service met the criteria in your medical policy [policy number and title] (or Medicare [LCD/NCD number]) and was necessary for the treatment of [diagnosis, ICD-10 code]. The enclosed records document that [patient] presented with [signs and symptoms], had [duration] of symptoms, and had already tried [conservative treatments] without adequate response, as your policy requires. The treating physician's letter explains why [service, CPT code] was the appropriate next step and what the expected outcome was. Each criterion in your policy is addressed in the attached summary, with page references to the records. We request a review by a physician in the same specialty as the treating provider, as permitted under [state law / your appeal procedures], reversal of the denial, and payment of [$ amount]. Sincerely, [Treating physician name, credentials] [Practice name] Enclosures: [list]

Copy letter[Practice name] [Practice address] [NPI / Tax ID] [Date] [Payer name], Appeals Department [Payer appeals address or fax] RE: Appeal of claim denial Patient: [Patient name] Member ID: [Member ID] Date of birth: [DOB] Claim number: [Claim number] Date of service: [DOS] Provider: [Rendering provider name, NPI] Billed amount: [$ amount] Denial reason code: [CARC/RARC] Dear Appeals Reviewer, We are appealing the denial of [CPT code] under reason code [CO-97 / CO-4 / CO-236] on the above claim. [CPT code A] and [CPT code B] were separate and distinct services performed [at different anatomical sites / during separate sessions / for separate lesions / through separate incisions], as documented in the enclosed procedure note. The NCCI edit for this code pair carries modifier indicator 1, permitting separate reporting with an appropriate modifier. Modifier [59 / XS / XE / XU] [was reported / has been added on the enclosed corrected claim] to identify the distinct service. [If modifier 25:] The evaluation and management service was significant and separately identifiable from the procedure performed the same day. The note documents a separate history, examination and medical decision making for [problem], beyond the usual pre- and post-procedure work. We request reprocessing of the claim with payment for [CPT code] in the amount of [$ amount]. Sincerely, [Name, title] Enclosures: [list]

Copy letter[Practice name] [Practice address] [NPI / Tax ID] [Date] [Payer name], Appeals Department [Payer appeals address or fax] RE: Appeal of claim denial Patient: [Patient name] Member ID: [Member ID] Date of birth: [DOB] Claim number: [Claim number] Date of service: [DOS] Provider: [Rendering provider name, NPI] Billed amount: [$ amount] Denial reason code: [CARC/RARC] Dear Appeals Reviewer, We are appealing the denial of the above claim under reason code CO-22 (care may be covered by another payer per coordination of benefits). [Option A, you are primary:] Our eligibility verification on [date] (enclosed) shows [Payer] as the patient's primary coverage on the date of service. The patient's other coverage with [other payer] [terminated on [date] / is secondary under the birthday rule / does not cover this service], as shown in the enclosed [termination letter / denial]. No other payer is responsible for this claim. [Option B, secondary filing:] The primary payer, [name], processed the claim on [date]; its remittance advice is enclosed showing an allowed amount of [$], paid [$], patient responsibility [$]. We are submitting this claim to [Payer] as secondary within [X] days of the primary remittance, as your timely filing rules for secondary claims require. We request that the denial be reversed and the claim processed for [$ amount]. Sincerely, [Name, title] Enclosures: [list]

Copy letter[Practice name] [Practice address] [NPI / Tax ID] [Date] [Payer name], Appeals Department [Payer appeals address or fax] RE: Appeal of claim denial Patient: [Patient name] Member ID: [Member ID] Date of birth: [DOB] Claim number: [Claim number] Date of service: [DOS] Provider: [Rendering provider name, NPI] Billed amount: [$ amount] Denial reason code: [CARC/RARC] Dear Appeals Reviewer, We are appealing the denial of the above claim under reason code CO-18 (exact duplicate claim/service). The claim is not a duplicate. [Choose one:] The patient was seen twice on [date], at [time] and [time], for [separate problems], as documented in the enclosed notes; modifier [27 / 76 / 77 / 91] identifies the repeat service. / The procedure was performed bilaterally and reported with [modifier 50 / RT and LT] on separate lines. / The original claim [claim number] was [rejected at the clearinghouse / never adjudicated], as shown in the enclosed report, so this submission is the first valid claim for these services. We request reprocessing and payment of [$ amount]. If a corrected claim (frequency code 7) is required instead of an appeal, please advise and we will submit it within [X] days. Sincerely, [Name, title] Enclosures: [list]

Copy letter[Practice name] [Practice address] [NPI / Tax ID] [Date] [Payer name], Appeals Department [Payer appeals address or fax] RE: Appeal of claim denial Patient: [Patient name] Member ID: [Member ID] Date of birth: [DOB] Claim number: [Claim number] Date of service: [DOS] Provider: [Rendering provider name, NPI] Billed amount: [$ amount] Denial reason code: [CARC/RARC] Dear Claims Department, Please find enclosed a corrected claim for the above patient, submitted in response to the denial under reason code CO-16 with remark code [N-code] ([remark text]). The original claim [omitted / contained an incorrect] [item: rendering provider NPI / diagnosis pointer / NDC and units / taxonomy code / place of service / referring provider]. The corrected claim carries frequency code 7 and references original claim number [ICN], with [item] corrected to [value]. No other data has changed. We request that the corrected claim be processed for payment of [$ amount] within the original timely filing period, as the original claim was received on [date]. Sincerely, [Name, title] Enclosures: corrected claim, remittance advice

Copy letter[Practice name] [Practice address] [NPI / Tax ID] [Date] [Payer name], Appeals Department [Payer appeals address or fax] RE: Appeal of claim denial Patient: [Patient name] Member ID: [Member ID] Date of birth: [DOB] Claim number: [Claim number] Date of service: [DOS] Provider: [Rendering provider name, NPI] Billed amount: [$ amount] Denial reason code: [CARC/RARC] Dear Appeals Reviewer, We request reconsideration of the denial of the above claim under reason code [CARC] with remark code [RARC], described on the remittance as “[denial text]”. The service was [covered under the member's plan / medically necessary / authorised / filed on time / correctly coded] for the following reason: [two or three sentences of fact, each tied to an enclosed document]. We request that the denial be reversed and the claim paid at [$ amount]. If additional information is needed, please contact [contact name, phone, email] rather than issuing a further denial, so that the matter can be resolved within your appeal timeframe of [X] days. Sincerely, [Name, title] [Practice name] Enclosures: [list]