Denial code · group CO
CO-109: This payer is not responsible for the claim; it belongs with another payer or contractor
Short answer
CO-109 means the payer that received the claim says it is not the one that covers this member, service or jurisdiction, and it will not process it. The service was not judged at all. The fix is to find the right payer from the eligibility response or the member's card, send that payer an original claim, and watch the filing window, because the clock did not stop while the wrong payer held the claim.
Look up other codes in the denial code library.
Last reviewed by the Remitwright billing team. Editorial policy
Group CO means contractual obligation: the balance is written off, not billed to the patient. The number is the reason; the two-letter group says who carries the balance.
Remark codes that usually come with CO-109
- N104
- The claim is not payable under this payer's claims jurisdiction
Common causes
The member is in a managed care plan, not the fee-for-service program
A Medicaid member enrolled in a managed care organization, or a Medicare beneficiary enrolled in a Medicare Advantage plan, and the claim went to the state program or the Medicare contractor. The fee-for-service payer returns it with CO-109 and N104.
A carve-out benefit
The medical plan contracts out behavioral health, pharmacy, vision, dental, transportation or another benefit to a separate administrator. The eligibility response often lists the other payer, but the claim went to the plan on the front of the card.
The wrong contractor or jurisdiction
Medicare and some state programs use different contractors for different claim types and regions. A claim sent to the contractor for the wrong claim type, or for a different region than the place of service, is returned rather than forwarded.
A hospice election
For a patient who has elected hospice, the payer may treat care related to the terminal illness as the hospice's to bill and return other providers' claims for it. The claim has to go through the hospice or carry the modifier that says the care was unrelated, depending on the payer's rule.
Another liable party
Workers' compensation, auto or liability coverage is responsible for the injury. The health plan says the claim belongs to that carrier rather than holding it under coordination of benefits.
A transportation claim sent to the wrong entity
In states where a broker manages the Medicaid transportation benefit, trips billed to the managed care plan or the state come back CO-109. In others the plan pays its own members' trips. Which one applies depends on the state, the program and the member's plan.
How to fix it and resubmit
- 1
Read the 271 for the date of service
The eligibility response shows the member's plan, the payer ID and, for carve-outs and managed care, the other payer's name. Compare it to the payer you billed. If the 271 shows the payer you billed as responsible, call that payer with the response before you do anything else.
- 2
Find the right payer and its claim rules
The back of the member's card, the state Medicaid enrollment lookup, the broker's provider portal or the hospice's contact all name who gets the claim. Confirm the payer ID, the claim format and whether the new payer needs its own authorization.
- 3
Send an original claim to the correct payer
This is a new claim to a payer that has never seen it, so it goes out with frequency code 1, not as a corrected claim. Include anything the new payer requires, such as a referral, trip authorization or hospice attestation.
- 4
Protect timely filing
The correct payer counts from the date of service, not from the day you found out. Send the claim the day the CO-109 posts. If its filing limit has already passed, file with proof of the original submission and the wrong payer's remittance; some payers accept that as good cause and some do not.
- 5
Fix the patient record
Update the insurance on file with the correct payer, plan and payer ID so the next visit does not repeat the round trip. For carve-outs, add the second payer record and mark which services go to which.
How to prevent it
- Eligibility checks that capture plan type, payer ID and any carve-out or managed care enrollment at every visit, not only coverage status
- A payer ID table in the practice management system that separates fee-for-service from managed care plans and each carve-out administrator
- An intake question on hospice election, workers' compensation and accident involvement for every visit with an injury or a Medicare patient
- For transportation providers, a state-by-state record of whether the broker, the managed care plan or the state pays trips for each program
A CO-109 with N104 on a carved-out behavioral health claim
A behavioral health group bills individual psychotherapy to the member's medical plan, the payer on the front of her card. The plan returns CO-109 with N104. Its behavioral health benefit is administered by a separate company named on the back of the card, and the 271 response had listed that company under a different payer ID. The biller loads the administrator as the payer for behavioral health services, sends an original claim within that company's filing limit, and keeps the medical plan's remittance in case the filing date is questioned. The claim pays. The group's intake now records both payers for every member of that plan. This is a hypothetical example.
Official text: the X12 claim adjustment reason code list. The meaning above is our paraphrase for billers; the list is the authority.
FAQ
Questions about CO-109
Is CO-109 the same as CO-22?
Does the wrong payer forward my claim?
What if the correct payer's filing limit has already passed?
The eligibility check said this payer was active. Why CO-109?
Who pays NEMT trips, the broker or the plan?
Next step
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