Denial Code 16 (CO-16, PR-16) — Meaning & What to Do
Claim Adjustment Reason Code (CARC)
What denial code 16 means: The claim is missing information or has an error that must be fixed before it can be processed.
What to do about denial code 16: Ask the provider's billing office to correct and resubmit — this is often fixable.
CO-16 vs PR-16 vs OA-16: what the prefix means
| Code on your EOB | What the prefix means | Who typically pays |
|---|---|---|
| CO-16 | Contractual obligation — the provider writes the amount off | Usually not the patient |
| PR-16 | Patient responsibility | The patient |
| OA-16 | Other adjustment | Often another payer or plan |
The prefix tells you who is expected to absorb the amount; the number (16) tells you why.
Seeing denial code 16 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 4The procedure code doesn't match a required modifier, or the modifier is missing/invalid.
CARC 18This looks like a duplicate of a claim already submitted.
CARC 3This amount is your copay — a fixed fee for the visit or service.
CARC 22Another insurance should be billed first (you may have primary coverage elsewhere).
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 16
What does denial code 16 mean on my EOB?
The claim is missing information or has an error that must be fixed before it can be processed.
What should I do about denial code 16?
Ask the provider's billing office to correct and resubmit — this is often fixable.
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.