Denial Code 110 (CO-110, PR-110) — Meaning & What to Do
Claim Adjustment Reason Code (CARC)
What denial code 110 means: The billing date comes before the service date.
What to do about denial code 110: A data error — ask the provider to correct the dates.
CO-110 vs PR-110 vs OA-110: what the prefix means
| Code on your EOB | What the prefix means | Who typically pays |
|---|---|---|
| CO-110 | Contractual obligation — the provider writes the amount off | Usually not the patient |
| PR-110 | Patient responsibility | The patient |
| OA-110 | Other adjustment | Often another payer or plan |
The prefix tells you who is expected to absorb the amount; the number (110) tells you why.
Related codes
CARC 108Adjusted under a rental/purchase rule for equipment.
CARC 111This provider isn't certified or eligible to be paid for this service.
CARC 107A related service or claim is required but wasn't found.
CARC 114This procedure or service isn't covered when done at home.
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 110
What does denial code 110 mean on my EOB?
The billing date comes before the service date.
What should I do about denial code 110?
A data error — ask the provider to correct the dates.
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.