Denial Code 109 (CO-109, PR-109) — Meaning & What to Do
Claim Adjustment Reason Code (CARC)
What denial code 109 means: This claim was sent to the wrong insurer or plan.
What to do about denial code 109: Confirm the correct insurer and ask the provider to resubmit.
CO-109 vs PR-109 vs OA-109: what the prefix means
| Code on your EOB | What the prefix means | Who typically pays |
|---|---|---|
| CO-109 | Contractual obligation — the provider writes the amount off | Usually not the patient |
| PR-109 | Patient responsibility | The patient |
| OA-109 | Other adjustment | Often another payer or plan |
The prefix tells you who is expected to absorb the amount; the number (109) tells you why.
Related codes
CARC 97This service is already included (bundled) in the payment for another service, so it isn't paid separately.
CARC 119A benefit maximum or limit for this service has been reached.
CARC 96This service is not covered by your plan.
CARC 197Pre-authorization or pre-certification was required but not obtained.
Keep reviewing your bill
- Medical Bill vs EOB: What Is the Difference?
- How to Dispute a Medical Bill — Find Billing Errors Before You Pay
Frequently asked questions about Denial code 109
What does denial code 109 mean on my EOB?
This claim was sent to the wrong insurer or plan.
What should I do about denial code 109?
Confirm the correct insurer and ask the provider to resubmit.
Found this code on your bill or EOB?
Upload the document — MD Bill Check decodes every code, checks the math line by line, and explains what's worth questioning.