Quick Explanation
Denial code CO-75 indicates that the secondary or subsequent insurance carrier has adjudicated the claim and applied the patient responsibility amount (such as deductible, copayment, or coinsurance) designated by the primary payer to the current claim. This adjustment occurs during the coordination of benefits (COB) process when the secondary payer calculates its liability based on the primary insurer's remittance details.
Common Causes for CO-75
Denials with code CO-75 typically happen for the following specific reasons:
- Incorrectly transferring or mapping the primary payer's claim adjustment reason codes (CARCs) and group codes into the electronic 837 secondary claim submission.
- The secondary plan containing a 'non-duplication of benefits' or 'carve-out' clause that limits payment to only what the secondary plan would have paid as primary.
- A discrepancy or mismatch between the primary payer's Explanation of Benefits (EOB) data and the COB information submitted to the secondary payer.
- Failure to submit the primary payer's complete remittance advice or EOB alongside the secondary claim.
How to Prevent CO-75 Denials
To avoid receiving this denial in the future, implement these specific checks:
- Configure billing software to automatically and accurately populate the primary insurance payment, contractual adjustments, and patient responsibility amounts in Loop 2320 and Loop 2430 of the 837 transaction.
- Perform a routine audit of secondary claims to ensure that the primary carrier's CAS segments (Claim Adjustment Segment) are fully and correctly mapped.
- Verify secondary insurance policy rules, specifically looking for restrictive coordination of benefits rules like non-duplication of benefits clauses, prior to billing.
- Ensure the billing team cross-references the paper or electronic EOB from the primary payer to ensure matching balances before submitting secondary claims.
Appeal Letter Template for CO-75
If you believe this claim was denied incorrectly, you can use the following template to submit an appeal.
[Your Practice Header]
[Date]
[Payer Name]
[Appeals Department Address]
RE: Appeal for Claim [Claim Number]
Patient: [Patient Name]
ID: [Patient ID]
Date of Service: [Date]
Denial Code: CO-75 - Prior payer's (or payers') patient responsibility (deductible, coinsurance, copayments) applied to this claim
Dear Appeals Department,
I am writing to appeal the denial of the above-referenced claim, which was denied with code CO-75: "Prior payer's (or payers') patient responsibility (deductible, coinsurance, copayments) applied to this claim".
We are appealing the coordination of benefits adjudication for this claim, which was processed with code CO-75. In accordance with CMS Coordination of Benefits (COB) guidelines and standard industry insurance practices, the secondary payer is responsible for reviewing and coordinating the patient responsibility (deductible, coinsurance, or copayment) established by the primary payer. The attached primary Explanation of Benefits (EOB) clearly demonstrates that the primary payer properly adjudicated the claim, leaving a designated patient responsibility of [Insert Amount]. As the secondary insurer, your policy should coordinate benefits to cover this remaining cost-share up to the allowed policy limits. We have verified that all primary billing details, including CAS segments, were correctly submitted. We request that you reprocess this claim and issue the appropriate secondary payment.
Attached please find:
1. A copy of the original claim.
2. The relevant medical records supporting the service.
3. [Any other supporting documents].
We respectfully request that you reprocess this claim for payment.
Sincerely,
[Your Name]
[Title]
[Practice Name]
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