Denial Code 251 (CO-251, PR-251) — Meaning & What to Do
Claim Adjustment Reason Code (CARC)
What denial code 251 means: The attachment or documentation needed to process this is missing.
What to do about denial code 251: Ask the provider to submit the required documentation.
CO-251 vs PR-251 vs OA-251: what the prefix means
| Code on your EOB | What the prefix means | Who typically pays |
|---|---|---|
| CO-251 | Contractual obligation — the provider writes the amount off | Usually not the patient |
| PR-251 | Patient responsibility | The patient |
| OA-251 | Other adjustment | Often another payer or plan |
The prefix tells you who is expected to absorb the amount; the number (251) tells you why.
Seeing denial code 251 on your EOB?
A denial code tells you what the payer reported, but it may not tell the whole story. Reviewing your EOB and bill together can help clarify what may need attention.
Related codes
CARC 246This service isn't payable per a payer's review decision.
CARC 253A federal sequestration (across-the-board) reduction was applied.
CARC 243Services aren't authorized by network or plan providers.
CARC 256This service isn't payable under a managed-care contract.
Keep reviewing your bill
- Medical Bill vs EOB: What Is the Difference?
- How to Dispute a Medical Bill — Find Billing Errors Before You Pay
- What Is an Itemized Medical Bill? How to Request One
Frequently asked questions about Denial code 251
What does denial code 251 mean on my EOB?
The attachment or documentation needed to process this is missing.
What should I do about denial code 251?
Ask the provider to submit the required documentation.
Seeing this code on your own EOB?
Upload the EOB, the bill, or both — MD Bill Check reads the codes on your documents, compares them side by side, and flags what's worth questioning. Free, no account needed.