Wrong payer or contractor
This payer does not handle this claim. Another payer, plan or Medicare contractor should receive it.
CO = Contractual Obligation. The provider owes the difference. The patient cannot be billed for this amount. The same reason code can appear with a different group code; the group decides who may be billed.
Usual causes
- Patient is in a Medicare Advantage plan and the claim went to traditional Medicare, or the reverse.
- Service belongs to a carve-out (behavioral health, dental, vision, pharmacy, DME).
- Wrong Medicare jurisdiction (N104) or Railroad Medicare (N105).
- Medicaid managed care plan instead of the state Medicaid agency.
The fix
Read the remark code for the right destination, verify eligibility for the date of service and send the claim to the correct payer with the original submission date noted.
Appeal or corrected claim?
Redirect; nothing to appeal here. Keep the denial as proof of timely filing for the correct payer.
Deadline to watch
The correct payer's timely filing limit from the date of service; many accept the first payer's denial as proof you filed on time.
Exact limits are in your payer contract or provider manual. When in doubt, send the correction or appeal this week.
Often seen together
Wrong payer: the claim was misrouted. Check the card and eligibility response for the correct payer ID and send it there.
CO-109 in short
What does CO-109 mean?
This payer does not handle this claim. Another payer, plan or Medicare contractor should receive it. The official X12 text reads: "Claim/service not covered by this payer/contractor. You must send the claim/service to the correct payer/contractor."
What usually causes a CO-109 denial?
Patient is in a Medicare Advantage plan and the claim went to traditional Medicare, or the reverse. Service belongs to a carve-out (behavioral health, dental, vision, pharmacy, DME). Wrong Medicare jurisdiction (N104) or Railroad Medicare (N105). Medicaid managed care plan instead of the state Medicaid agency.
How do I fix CO-109?
Read the remark code for the right destination, verify eligibility for the date of service and send the claim to the correct payer with the original submission date noted.
Should I appeal CO-109 or send a corrected claim?
Call or redirect. Redirect; nothing to appeal here. Keep the denial as proof of timely filing for the correct payer.
What deadline applies to CO-109?
The correct payer's timely filing limit from the date of service; many accept the first payer's denial as proof you filed on time.