How do I resolve a CO-16+N425 denial?

Verify the service against payer's statutory exclusion list: Confirm the specific service code is indeed statutorily excluded under federal or state law for this payer type Post the contractual adjustment as a write-off in the practice management system: Apply CO adjustment to the claim balance without transferring any amount to patient responsibility Update billing procedures to prevent future submissions of this statutorily excluded service: Add the service code to billing system edits or scrubber rules to flag or block similar claims before submission

835 Denial Combination

CO-16+N425

Contractual Obligation · Claim-Level Adjustment

Missing Information

What This Combination Means

This combination indicates the claim was submitted with billing errors or missing information for a service that is statutorily excluded from coverage. The N425 clarifies that CARC 16's submission error relates to attempting to bill a service that federal or state law prohibits the payer from covering. The payer is flagging both the billing mistake and the underlying statutory exclusion.

Financial Responsibility

provider writeoff

The provider must write off this amount due to contractual obligations. The service cannot be billed to the patient because it is statutorily excluded and the claim had submission errors.

N/A

Appeal Success

Immediate (write-off)

Avg. Resolution

Easy

Difficulty

Appealable

Step-by-Step Resolution

Steps tailored specifically to this CO-16+N425 combination — not generic advice.

Not Appealable:Statutorily excluded services cannot be appealed as they are prohibited by law from coverage, and the CO adjustment requires contractual write-off.

1
Verify the service against payer's statutory exclusion list
Confirm the specific service code is indeed statutorily excluded under federal or state law for this payer type
2
Post the contractual adjustment as a write-off in the practice management system
Apply CO adjustment to the claim balance without transferring any amount to patient responsibility
3
Update billing procedures to prevent future submissions of this statutorily excluded service
Add the service code to billing system edits or scrubber rules to flag or block similar claims before submission

Specialty Context

How CO-16+N425 typically presents across different practice types.

Dental

May apply to services excluded under medical insurance policies when dental procedures are billed to medical carriers, such as routine dental care or cosmetic dental services not covered by law.

Medical

Common for services like cosmetic procedures, experimental treatments not FDA-approved, or specific services excluded under Medicare statute such as hearing aids, routine foot care for non-diabetic patients, or certain screening services.

Behavioral Health

May occur when billing services excluded under mental health parity laws or state statutes, such as court-ordered evaluations, services for educational purposes only, or treatments not meeting medical necessity definitions under statute.

Individual Code References

View the standalone definition for each code in this combination.

CARC 16 RARC N425

Medicare Contractor Guidance for CARC 16

FCSO + Noridian + uhc + aetna + bcbs_az

This RUC is received when a claim is submitted with missing, incorrect, or invalid information. For details pertaining to your claim, please refer to the remittance advice remark codes (RARCs) on the remittance advice (RA).

How to Prevent CARC 16 Denials

✓
Review the RARC on the remittance advice to identify which specific field has the error.
✓
Per Medicare guidelines, claims must be filed no later than 12 months after the date of service. RUCs are not considered filed/submitted.

CMS guidelines for completion of form CMS-1500 in the Medicare Claims Processing Manual (100-04), Chapter 26SPOTFee Schedule Lookup ToolCMS laboratory demographics lookupModifier lookup toolNoridian Medicare PortalNMPIVRSame or SimilarPECOSPDAC

Need to resolve this denial?

Get a complete resolution plan with appeal guidance for this exact combination in seconds.

Generate a free resolution plan & appeal letter →

Synthesized from official definitions — not from training data

Was this helpful?

← Back to Combo Lookup Browse All Codes →