Appeal — TEST-CLAIM-00084

Date: [Letter Date]

Via: [Submission Method]

Synthetic Cigna
[Payer Address]
[City, State, ZIP]

Re: Formal Appeal of Claim Denial
Claim Number: TEST-CLAIM-00084
Payer: Synthetic Cigna
Service Date: February 26, 2026
Denial Date: April 30, 2026
Denial Reason: CO-45 – Charges Exceed Contracted/Legislated Fee Arrangement
Total Billed: $2,409.33
Amount Denied: $1,731.15
Appeal Deadline: August 28, 2026

Dear Synthetic Cigna Appeals Department,

On behalf of [Hospital/Facility Name] (hereinafter "the Facility"), we are submitting this formal first-level appeal contesting the denial issued on April 30, 2026 for Claim TEST-CLAIM-00084. The claim was denied under adjustment reason code CO-45, with the stated basis that billed charges exceed the contracted/legislated fee arrangement. The Facility respectfully disagrees with this determination and requests that Synthetic Cigna reprocess the claim and issue payment of the denied amount of $1,731.15.

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I. BACKGROUND

The Facility rendered medically necessary services on February 26, 2026 for a patient with documented diagnoses of Type 2 diabetes with diabetic skin complications (ICD-10: E11.71) and a fracture of the tibia (ICD-10: S82.36). The procedures performed were billed under CPT codes 94843, 53863, and 18639. The total billed amount was $2,409.33. Upon adjudication, Synthetic Cigna applied an allowed amount of only $678.18 and denied the remaining $1,731.15 under CO-45, asserting that the billed charges exceeded the contracted fee arrangement.

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II. BASIS FOR APPEAL

The Facility contests this denial on the following grounds:

• MISAPPLICATION OF THE CONTRACTED FEE SCHEDULE: The Facility maintains a fully executed fee schedule agreement with Synthetic Cigna. A thorough review of the contracted allowable rates for CPT codes 94843, 53863, and 18639 indicates that the allowable amount of $678.18 applied by Synthetic Cigna does not accurately reflect the negotiated rates for these procedure codes as set forth in the parties' agreement. The Facility believes the payer has misapplied or incorrectly looked up the applicable contracted rates, resulting in a significant underpayment.

• RATE LOOKUP OR CALCULATION ERROR: CO-45 denials predicated on contract disputes are frequently the result of rate table errors, incorrect effective-date application, or fee schedule version mismatches. A line-by-line comparison of the contracted allowable per procedure code against the adjudicated amounts submitted herewith strongly suggests that the $1,731.15 reduction reflects a computational or system error rather than a legitimate overage under the contract.

• BILLED CHARGES ARE CONSISTENT WITH FACILITY COST STRUCTURE: The Facility's billed charges for the three procedure codes at issue are derived from and consistent with its documented fee-setting methodology and hospital billing policy. The enclosed itemized facility charge breakdown by procedure code and the hospital billing policy and fee-setting documentation confirm that the billed amounts reflect legitimate facility costs and are not in excess of the Facility's standard charge schedule.

• SUPPORTING DOCUMENTATION ESTABLISHES CORRECT CONTRACTED ALLOWABLE: The enclosed contracted fee schedule with Synthetic Cigna, the itemized facility charge breakdown, and the comparison of billed amounts versus contracted allowable amounts collectively demonstrate that the allowable for the services rendered on February 26, 2026 materially exceeds the $678.18 applied by Synthetic Cigna. The Facility respectfully requests that Synthetic Cigna perform a line-by-line review of each CPT code against the current, applicable fee schedule to confirm the correct contracted rates.

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III. SUPPORTING DOCUMENTATION

The following documents are enclosed in support of this appeal:

1. Contracted fee schedule with Synthetic Cigna, identifying the applicable allowable rates for CPT codes 94843, 53863, and 18639
2. Itemized facility charge breakdown by procedure code for the services rendered on February 26, 2026
3. Comparison of billed amounts versus contracted allowable amounts by CPT code
4. Operative report and/or procedure documentation supporting the medical necessity and accuracy of the billed procedure codes
5. Hospital billing policy and fee-setting documentation

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IV. POLICY BASIS

Pursuant to the contracted fee schedule rate agreement between the Facility and Synthetic Cigna, the payer is obligated to adjudicate claims in accordance with the negotiated rates applicable to each covered procedure code. A CO-45 denial is only appropriate where the billed amount genuinely exceeds the contracted allowable for the service at issue. Where, as here, the fee schedule documentation supports a higher allowable than the amount applied, the payer's rate calculation is subject to direct challenge and correction. The Facility asserts that the adjudicated allowable of $678.18 does not reflect the correct application of the contracted fee schedule and constitutes a misapplication of the parties' agreement.

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V. REQUESTED REMEDY

The Facility respectfully requests that Synthetic Cigna:

1. Conduct a line-by-line review of the contracted allowable rates for CPT codes 94843, 53863, and 18639 against the enclosed fee schedule documentation;
2. Reprocess Claim TEST-CLAIM-00084 using the correct contracted allowable rates as established by the enclosed documentation; and
3. Issue payment of the denied amount of $1,731.15, plus any applicable interest as required under the parties' agreement and applicable state prompt payment regulations.

This appeal is being submitted in advance of the August 28, 2026 appeal deadline. The Facility reserves all rights, including the right to pursue additional levels of appeal, arbitration, or other remedies available under the contract and applicable law, should this appeal not be resolved in the Facility's favor.

We appreciate Synthetic Cigna's prompt attention to this matter and welcome the opportunity to provide any additional documentation or clarification that may assist in the review. Please direct all correspondence regarding this appeal to:

[Hospital/Facility Name]
[Contact Name and Title]
[Address]
[Phone Number]
[Email Address]

Respectfully submitted,

[Authorized Signatory Name]
[Title]
[Hospital/Facility Name]
[Date]