Denial Code 23 (CO-23, PR-23) — Meaning & What to Do
Claim Adjustment Reason Code (CARC)
What denial code 23 means: Payment was affected by a prior payer's decision (coordination of benefits).
What to do about denial code 23: Review both insurers' statements to confirm the combined amounts are correct.
CO-23 vs PR-23 vs OA-23: what the prefix means
| Code on your EOB | What the prefix means | Who typically pays |
|---|---|---|
| CO-23 | Contractual obligation — the provider writes the amount off | Usually not the patient |
| PR-23 | Patient responsibility | The patient |
| OA-23 | Other adjustment | Often another payer or plan |
The prefix tells you who is expected to absorb the amount; the number (23) tells you why.
Seeing denial code 23 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 22Another insurance should be billed first (you may have primary coverage elsewhere).
CARC 27Coverage had ended when this service was provided.
CARC 18This looks like a duplicate of a claim already submitted.
CARC 29The claim was submitted too late (past the filing deadline).
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 23
What does denial code 23 mean on my EOB?
Payment was affected by a prior payer's decision (coordination of benefits).
What should I do about denial code 23?
Review both insurers' statements to confirm the combined amounts are correct.
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.