What does denial code CO-109 mean?

CO-109 means: The claim was sent to the wrong insurance company. The patient's coverage for this service is through a different payer, and the claim must be resubmitted to the correct insurance carrier.. The first step in avoiding the reason code CO 109 is to check what type of insurance coverage the patient has and verify their eligibility status prior to submitting claims to Medicare. If the claim has been filed to Medicare in error, it will be returned as an unprocessable claim and will need to be resubmitted to the correct payer / contractor for payment.

How do I resolve a CO-109 denial?

If wrong date of service was billed, suppliers may do a self service reopening in the Noridian Medicare Portal. When provided within 2 days prior to anticipated discharge to home, the discharge date must be billed If beneficiary was not inpatient on date items were provided, contact the facility to update their billing. You can find the NPI of the facility through the claim status page under expanded denial details of the NMP for that specific claim. Once that billing update is verified through Self Service, supplier can either do a self service reopening or rebill the claim for the correct date of service. See full Medicare contractor resolution steps at tryarceum.com.

Can I appeal a CO-109 denial?

CO-109 denials are generally not appealable. This is a routing issue rather than a coverage decision, so appeal is not appropriate; the claim must be sent to the correct payer.

CARC Code

109

🔴 Hard Denial

Wrong Payer Submission

The claim was sent to the wrong insurance company. The patient's coverage for this service is through a different payer, and the claim must be resubmitted to the correct insurance carrier.

eligibility

Resolution: 55%Medium difficulty14-30 days avg

How to resolve this denial

Which payer denied this claim?

▶✓ Pre-action checklist — verify before contacting the payer

Review the full remittance advice (ERA/EOB) for additional RARC codes that explain the denial.
Verify the claim was submitted with correct patient eligibility and benefit information.
Check if this denial applies to a specific line item or the entire claim.

Still denied?

Formal Appeal

If the payer upheld the denial after reconsideration, you can submit a formal appeal.

Generate appeal letter →

▶More about CO-109 — stats, related codes, appeal template

55%

Recovery Rate

14-30 days

Avg. Resolution

Medium

Difficulty

Occasional

Frequency

Payer-Specific Notes

How major payers handle CARC 109 by specialty.

Blue Cross Blue Shield

BCBS requires appeal submission within 180 days for most plans.

Common 835 Combinations

CARC 109 most often appears with these Group Code + RARC combinations on 835 remittances.

COCO-109This combination indicates the claim was submitted to the wrong payer or COCO-109+MA130The payer has determined they are not the correct payer for this claim, but the COCO-109+N538Beneficiary was inpatient on date of service COCO-109+N104Claim was submitted to incorrect Jurisdiction Claim must be submitted to the COCO-109+N130Claim was submitted to incorrect contractor Was beneficiary inpatient on date COCO-109+N418Claim was billed to incorrect contractor For date of service submitted,

Look up any combination →

Appeal Letter Template

Generic appeal template for CARC 109 denials.

We are submitting a formal appeal for claim [CLAIM_NUMBER] for patient [PATIENT_NAME], date of service [DOS]. This claim was denied/adjusted with CARC 109 indicating: "Claim/service not covered by this payer. Send to correct payer/contractor.." We have reviewed the claim and are providing the attached documentation to support reconsideration. [SUPPORTING_DOCUMENTATION]. Please reconsider payment per the terms of our contract.

Generate a personalized appeal letter →

Need to resolve this denial?

Get a step-by-step resolution plan with payer-specific guidance and appeal letter generation.

Resolve this denial →

Was this helpful?

← Back to Code Library Automate denial follow-up →