The CO-290 denial code means the dental plan found no dental benefit for the service and forwarded the claim to the patient’s medical plan. You do not need to refile yet. Confirm that the medical plan received it, give it time to process, and answer any record requests quickly. (Primary source: X12 Claim Adjustment Reason Codes)
In brief: CARC 290 is a routing notice. The twin code, CARC 254, means the dental plan did not forward the claim, so you must. With CO-290, hold the balance and track the medical claim; do not bill the patient yet.
Part of our denial codes library. Written by Manikandan J, CPC, CRCR, who has tracked forwarded dental-to-medical claims for oral surgery and periodontal practices. Published 13 November 2026. Last updated: 13 November 2026. Code wording quoted word for word from X12. Read about the author and our editorial policy, or contact us to report an error.
What does denial code CO-290 mean?
Denial code CO-290 means the dental plan closed its part with no payment and passed the claim to the medical plan. Reason code 290 is common when one company runs both benefits. The dental zero is not the final answer on the service.
| Field | Value |
|---|---|
| Code | 290 |
| Description | “Claim received by the dental plan, but benefits not available under this plan. Claim has been forwarded to the patient’s medical plan for further consideration.” |
| Group codes | No X12 group restriction; CO and OA both appear |
| Start | 11/01/2017 |
| X12 note | Use CARC 254 if the claim was not forwarded |
Source: X12 Claim Adjustment Reason Codes, checked 13 November 2026.
Methodology: the code wording is copied from the X12 list, and the handling steps follow the X12 note on CARC 254 and the claim form sources cited below.
Key terms: A forwarded claim is one the payer moved to the other plan for you. The medical benefit is the coverage under the patient’s health plan, not the dental plan. CO is the contractual obligation group code.
CO-290 vs OA-290: what is the difference?
CO-290 means the dental plan you contract with posted the zero as a contractual adjustment while the claim moves on. OA-290 shows the same handoff without assigning any responsibility, which many plans prefer for a routing notice. In both cases, the medical plan’s decision is the one that counts.
| Version | How to post the dental remittance | What to wait for |
|---|---|---|
| CO-290 | Zero pay, hold the balance in a forwarded-to-medical status | The medical plan’s own remittance |
| OA-290 | Same posting, no liability named | The medical plan’s own remittance |
Never move a CO-290 balance to the patient while the medical plan is still deciding.
Why did the dental plan forward the claim?
The dental plan forwards a claim when the service looks medical rather than dental. Oral biopsies, jaw fractures, cyst removal and treatment linked to an accident are common examples. The plan decides its dental benefit does not apply but the medical plan might.
Forwarding only works when the plan knows the patient’s medical coverage. That is why it is common when one carrier runs both plans. If the plan cannot forward, you get CARC 254 and must file the medical claim yourself, as the X12 note on CARC 290 says.
Example scenario (fictional names), part 1
CO-290 Denial Example: What Happened
Noah Bennett bills for Eastlake Oral Surgery. Dr. Helena Ruiz took an incisional biopsy of a lesion on the floor of the mouth and sent the claim to the dental plan with D7286.
The fictional carrier runs both the patient’s dental and medical plans.
The dental 835 came back with CAS*CO*290 and a zero payment. Thirty days later the medical side had not paid. The patient called to ask if the bill was theirs.
Should Noah refile on a medical claim, or wait? Keep reading, or jump to how it was resolved. Keep reading, or jump to how the CO-290 denial was resolved.
How do I handle a CO-290 denial?
To handle a CO-290 denial, post the dental zero, hold the balance and track the claim at the medical plan. Call to confirm it arrived and ask for its new claim number. If the medical plan has no record after a reasonable time, file a medical claim yourself with the dental remittance as proof.
- Post and hold. Record the dental zero and flag the account as forwarded to medical.
- Confirm receipt. Call the medical plan and note the new claim number.
- Answer requests. Send pathology reports or notes the medical plan asks for.
- File only if lost. If the medical plan has no claim, submit one on the CMS-1500 with medical codes.
- Work the medical decision. If the medical plan denies, treat that as a new denial.
Example scenario (fictional names), part 2
How the CO-290 Denial Was Resolved
Noah called the medical plan. It had received the forwarded claim, but it was pended for the pathology report.
Fix: Noah faxed the report and Dr. Ruiz’s operative note to the medical plan, quoting its new claim number. He did not refile, which would have created a duplicate. He told the patient the claim was still in review.
Outcome: the medical plan processed the forwarded claim and paid the biopsy under the medical benefit. Noah now sets a 21-day follow-up on every CO-290.
Names and details are illustrative; no real patient data.
Names and details are illustrative; no real patient data.
Will refiling after CO-290 cause a duplicate denial?
Yes, refiling too early can cause a duplicate denial. The medical plan already has the forwarded claim, so a second claim for the same service can come back as CO-18, an exact duplicate denial. Always confirm the status first. Refile only when the medical plan says it has no record.
Can I bill the patient for CO-290?
No, not while the medical plan is deciding. CO-290 is a contractual zero on the dental side, not patient responsibility. Wait for the medical remittance. Any patient share will show there as PR, such as a deductible or coinsurance. For example, a biopsy paid under the medical benefit may still leave a deductible, as described in the HealthCare.gov deductible definition.
Related codes
| Code | Meaning |
|---|---|
| CO-254 | Dental plan: submit to the medical plan yourself |
| CO-270 | Medical plan: submit to the dental plan |
| CO-280 | Medical plan: submit to the pharmacy plan |
| CO-18 | Exact duplicate claim or service |
FAQ
What does CO-290 mean?
The dental plan found no benefit and forwarded the claim to the patient’s medical plan.
Do I need to refile a CO-290 claim?
Not at first. Confirm the medical plan received it, and refile only if it did not.
Is CO-290 the same as CO-254?
No. CO-254 means the claim was not forwarded. CO-290 means it was.
Which group code comes with CARC 290?
X12 sets no restriction. CO and OA both appear on dental remittances.
Does the patient owe a CO-290 amount?
No. Wait for the medical plan’s decision before billing anything.
Sources
How we checked: the CARC 290 quote was matched word for word with the X12 CARC list on 13 November 2026, including the X12 note pointing to CARC 254.
- X12, Claim Adjustment Reason Codes (CARC 290, 254, 18). Accessed 13 Nov 2026.
- X12, Remittance Advice Remark Codes. Accessed 13 Nov 2026.
- ADA, Code on Dental Procedures and Nomenclature (CDT). Accessed 13 Nov 2026.
- NUCC, 1500 claim form instructions. Accessed 13 Nov 2026.
- HealthCare.gov, dental coverage in the Marketplace. Accessed 13 Nov 2026.
Last updated: 13 November 2026 · Educational content; not legal advice.