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CO-180 Denial Code: Residency Requirement Not Met

CO-180 means the patient has not met the required residency requirements. The plan or program, typically a state Medicaid program or a regional plan, requires the patient to live in a particular state or service area, and the payer found they did not.

Quick facts

Code
CO-180 (CARC 180)
Status
Active In use since June 30, 2005; last modified September 30, 2007.
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The provider absorbs the amount from this payer's decision. Program rules may restrict billing the patient.
  • PR (Patient Responsibility): The patient may be responsible because they do not qualify under the program's residency rules. Check program rules and any other coverage first.
Official description
Patient has not met the required residency requirements.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-180 means

CARC 180 reads “Patient has not met the required residency requirements.” Government programs like Medicaid are run by states, and each generally requires that enrollees live in the state. Some plans also limit coverage to residents of a service area. When the payer concludes the patient doesn’t meet the residency rule, it denies with this code.

It’s uncommon, and it usually signals either a move, a demographic data mismatch, or a patient whose enrollment status is under review.

Example: a patient enrolled in one state’s Medicaid program moves to a neighboring state and continues treatment. The original program determines the patient no longer lives in the state and denies claims after the move date with CO-180.

Common causes

  • Patient moved out of the state or service area.
  • Address mismatch between the claim (box 5) and the payer’s enrollment records.
  • Program redetermination that found the patient no longer meets residency.
  • Temporary stays away from home, where the program’s rules on out-of-state residence apply.

How to fix it

  1. Confirm the patient’s current address and when they moved, if they did.
  2. If demographics were wrong, correct the address in your system and on the claim, and ask the payer to reprocess or submit a corrected claim with resubmission code 7.
  3. If the patient moved, help them apply for coverage in the new state, and ask whether that program allows retroactive coverage for the service dates.
  4. If the patient is a resident and the payer is wrong, the patient can dispute the determination with the program. Hold the account while that proceeds.
  5. Bill the patient only if no coverage applies and the group code and program rules allow it.

How to prevent it

  • Confirm addresses at every visit, not just at intake.
  • Run eligibility checks and watch for plan or program changes that suggest a move.
  • Ask patients about upcoming moves during ongoing treatment.
  • Know the out-of-state rules of the programs you bill most. See eligibility and COB denials.

Specialty notes

Providers near state borders and those treating mobile populations, such as students or seasonal workers, are most likely to see this code.

Remark codes that may appear with CO-180

  • N30 (Patient ineligible for this service.): The patient is ineligible for the service under this program.
  • M21 (Missing/incomplete/invalid place of residence for this service/item provided in a home.): The place of residence reported for a home service is missing or invalid.
  • CO-177 (Patient has not met the required eligibility requirements.): A general eligibility requirement was not met.
  • CO-31 (Patient cannot be identified as our insured.): The patient cannot be identified as the payer's insured.
  • CO-109 (Claim/service not covered by this payer/contractor.): The claim should go to another payer or contractor, sometimes because of location.

CO-180 FAQ

Which payers use CO-180?

Mainly state Medicaid programs and other state or regional programs with residency rules, and some plans tied to a specific service area.

What if the patient recently moved?

They may need to enroll in the new state's program. Coverage in the old state often ends after the move, while new coverage may begin at application or another date set by the new state's rules.

Can a wrong address cause CO-180?

Yes. If the patient's address on the claim or in the payer's records is wrong, the payer may think the patient lives outside the service area. Correct the demographics and ask the payer to reprocess.

Does a temporary stay out of state trigger CO-180?

Not always. Many programs keep coverage during temporary absences, while emergency care out of state may follow its own rules. The program's residency and out-of-state service policies decide the outcome.