How do I resolve a CO-50+N180 denial?

If the remittance advice reason includes MA130, correct claim and rebill A redetermination request may be submitted with all relevant supporting documentation. Noridian encourages Redeterminations/Appeals be submitted using the Noridian Medicare Portal. Review applicable Local Coverage Determination (LCD), LCD Policy Article, and Documentation Checklists prior to submitting request. If the KX modifier was omitted by mistake, request a Redeterminations/Appeals to add, change, or remove the KX (the same is true for GA, GZ, GY modifiers). Be sure to include all the appropriate documentation.

Can I appeal a CO-50+N180 denial?

CO-50+N180 denials are generally not appealable. Claim is missing the KX modifier. This is not a service covered by Medicare.

835 Denial Combination

CO-50+N180

Contractual Obligation · Service-Line Level Adjustment

What This Combination Means

Claim is missing the KX modifier. This is not a service covered by Medicare.

N/A

Appeal Success

7-14 days

Avg. Resolution

Medium

Difficulty

Appealable

Step-by-Step Resolution

Steps tailored specifically to this CO-50+N180 combination — not generic advice.

1
If the remittance advice reason includes MA130, correct claim and rebill
2
A redetermination request may be submitted with all relevant supporting documentation. Noridian encourages Redeterminations/Appeals be submitted using the Noridian Medicare Portal. Review applicable Local Coverage Determination (LCD), LCD Policy Article, and Documentation Checklists prior to submitting request.
3
If the KX modifier was omitted by mistake, request a Redeterminations/Appeals to add, change, or remove the KX (the same is true for GA, GZ, GY modifiers). Be sure to include all the appropriate documentation.

Specialty Context

How CO-50+N180 typically presents across different practice types.

Dental

Medical

Behavioral Health

Individual Code References

View the standalone definition for each code in this combination.

CARC 50 RARC N180

Medicare Contractor Guidance for CARC 50

FCSO + Noridian + uhc + aetna + bcbs_az

This denial reason code is received when a procedure code is billed with an incompatible diagnosis for payment purposes, and the ICD-10 code(s) submitted is/are not covered under an LCD or NCD.

How to Prevent CARC 50 Denials

✓
Refer to the Active / Future / Retired LCDs medical coverage policies for a list of procedure codes relating to services addressed in the LCD, and the diagnoses for which a service is or is not considered medically reasonable and necessary.
✓
Report only the diagnosis(es) for the treatment date of service.
✓
Be proactive, and stay informed on Medicare rules and regulations, and maximize the self-service tools available on the First Coast website.

CMS IOM Pub. 100-08, Chapter 13 - Local Coverage DeterminationsNoridian Medicare PortalModifier Lookup Tool

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