835 Denial Combination

CO-16+N411

CO

Contractual Obligation · Claim-Level Adjustment

Missing/Invalid Information

What This Combination Means

The claim was denied due to a billing error related to service frequency limitations. The payer identified that the billed service exceeds the allowed frequency of once per 6-month period under the provider's contract. The RARC N411 clarifies that the submission error (CARC 16) specifically involves violating the contractual frequency limit.

Financial Responsibility

provider writeoff

Provider must write off the denied amount as a contractual adjustment. The claim was submitted in error against known frequency limits, making this a provider billing error that cannot be passed to the patient.

N/A

Appeal Success

Immediate (write-off)

Avg. Resolution

Easy

Difficulty

No

Appealable

Step-by-Step Resolution

Steps tailored specifically to this CO-16+N411 combination — not generic advice.

Not Appealable:This is a contractual frequency limitation enforced under the provider's agreement with the payer, and the billing error is the provider's responsibility to prevent.
  1. 1

    Verify the service date and previous claim history for this patient

    Confirm when the same service was last performed and paid to validate the 6-month frequency rule was indeed violated

  2. 2

    Write off the denied amount as a contractual adjustment

    Post the adjustment with CO-16 and reference the frequency limitation in billing system notes

  3. 3

    Update billing edits to flag this service code for 6-month frequency checks

    Implement automated scrubbing rules to prevent future claims from being submitted before the 6-month period elapses for this service

Specialty Context

How CO-16+N411 typically presents across different practice types.

Dental

Commonly applies to preventive services like prophylaxis (D1110) or comprehensive exams that are limited to twice annually, or periodontal maintenance (D4910) when submitted more frequently than quarterly or semi-annually per contract terms

Medical

Frequently seen with preventive services such as routine screenings, wellness visits, or high-cost diagnostics like bone density scans that have contractual frequency limits built into fee schedules

Behavioral Health

May apply to psychological testing batteries or comprehensive assessments that are contractually limited to once per benefit period to prevent redundant diagnostic evaluations

Individual Code References

View the standalone definition for each code in this combination.

CARC 16RARC N411

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

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Synthesized from official definitions — not from training data

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