CO-180: Residency Requirements Not Met

What Does CO-180 Mean?

CO-180 is a contractual write-off indicating the provider billed for a patient who does not meet the plan's residency requirements. The provider should have verified residency as part of the eligibility check before rendering services. However, if the patient can provide residency documentation that was not originally submitted, the denial can be overturned through appeal.

CARC 180 indicates that the payer denied the claim because the patient does not satisfy the plan's residency criteria. Many insurance plans — particularly Medicaid, state-funded programs, HMOs, and regional plans — require patients to reside within a defined geographic area to maintain eligibility. When the payer's records show the patient lives outside the coverage zone or cannot verify residency, the claim is denied under this code.

This denial surfaces in several scenarios: the patient relocated out of the plan's service area but did not update their insurer; the patient is a student, temporary worker, or seasonal resident whose primary residence is elsewhere; or the patient's address on file is simply incorrect or outdated. For Medicaid specifically, residency requirements vary by state and can include minimum duration thresholds, proof of domicile, and verification documents like utility bills or lease agreements.

The code appears with both CO and PR group codes. CO-180 indicates a provider write-off, typically when the provider should have verified the patient's residency as part of eligibility checking. PR-180 places the charges on the patient because they enrolled in or maintained a plan they are not geographically eligible for. Resolution hinges on whether the patient can provide proof of residency — if they can, appeal with documentation; if they genuinely live outside the service area, the charges fall to the patient or must be written off.

Common Causes

How to Resolve

Verify the patient's current residency status, collect proof of residency if they do meet the requirements, and appeal or bill the patient depending on the outcome.

1. Review payer residency criteria Check the specific residency requirements for the patient's plan — geographic boundaries, minimum duration, and acceptable proof documents.
2. Collect proof of residency Obtain residency documentation from the patient: utility bills, lease agreement, state ID, or voter registration within the coverage area.
3. Appeal with residency proof Submit a formal appeal with the residency documentation. Include the patient's enrollment records and a statement explaining the residency status.

Common RARC Pairings

The RARC code tells you exactly what triggered the CO-180:

How to Prevent CO-180

• Include residency verification as part of the patient registration workflow, especially for state-specific plans and Medicaid
• Collect a copy of the patient's state-issued ID or proof of address during registration
• Implement automated address verification that flags patients whose addresses fall outside the plan's service area
• Schedule periodic patient demographic reviews to catch address changes before they trigger denials

General Prevention

• Verify patient residency status and address during registration and at every visit, particularly for patients with state-specific or regional plans
• Collect and verify proof of residency documents as part of the patient intake process
• Implement automated address verification in the practice management system to flag discrepancies
• Educate patients about their plan's residency requirements and the importance of updating address information with their insurer
• Train front desk and registration staff on payer-specific residency requirements
• Conduct regular audits of patient demographic information to identify and correct outdated addresses

Also Filed As

The same CARC 180 may appear with different Group Codes:

Related Denial Codes