Denial Code 11 (CO-11, PR-11) — Meaning & What to Do
Claim Adjustment Reason Code (CARC)
What denial code 11 means: The diagnosis doesn't match the procedure that was billed.
What to do about denial code 11: Ask the provider's billing office to explain or correct this, and resubmit if needed.
CO-11 vs PR-11 vs OA-11: what the prefix means
| Code on your EOB | What the prefix means | Who typically pays |
|---|---|---|
| CO-11 | Contractual obligation — the provider writes the amount off | Usually not the patient |
| PR-11 | Patient responsibility | The patient |
| OA-11 | Other adjustment | Often another payer or plan |
The prefix tells you who is expected to absorb the amount; the number (11) tells you why.
Related codes
CARC 9The diagnosis doesn't match the patient's age.
CARC 13The date of service is after the patient's date of death on record.
CARC 8The procedure code doesn't match the provider's specialty.
CARC 15The authorization number is missing, invalid, or doesn't apply to this service.
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 11
What does denial code 11 mean on my EOB?
The diagnosis doesn't match the procedure that was billed.
What should I do about denial code 11?
Ask the provider's billing office to explain or correct this, and resubmit if needed.
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.