835 Denial Combination

CO-16+N504

CO

Contractual Obligation · Claim-Level Adjustment

Missing Information

What This Combination Means

The claim was denied because a required Work Status Report is either incomplete or invalid. This typically occurs for workers' compensation claims, disability claims, or other cases where employment status and work capacity documentation is required to support the medical necessity or eligibility for services. The provider is contractually obligated to write off the denied amount and must submit a complete and valid Work Status Report to secure payment.

Financial Responsibility

provider writeoff

Provider must write off the denied amount under contractual obligation. The patient cannot be billed for this adjustment while the work status documentation deficiency remains unresolved.

N/A

Appeal Success

2-4 weeks (corrected claim)

Avg. Resolution

Medium

Difficulty

No

Appealable

Step-by-Step Resolution

Steps tailored specifically to this CO-16+N504 combination — not generic advice.

Not Appealable:This is a billing error due to missing required documentation, not a coverage or medical necessity dispute; correction requires resubmission with complete information rather than appeal.
  1. 1

    Obtain complete Work Status Report from treating provider

    The report must include all required fields such as patient work capacity, functional limitations, return-to-work dates, and restrictions specific to the patient's employment

  2. 2

    Validate Work Status Report against payer-specific requirements

    Confirm the report format, signature requirements, date ranges, and specific work capacity language meet the payer's documentation standards for workers' compensation or disability claims

  3. 3

    File corrected claim with complete Work Status Report attached

    Submit using corrected claim frequency code (7) with the valid Work Status Report, ensuring all other claim elements remain accurate and reference the original claim number

Specialty Context

How CO-16+N504 typically presents across different practice types.

Dental

Medical

Common in occupational medicine, orthopedics, physical medicine, and pain management where Work Status Reports document patient functional capacity and return-to-work timelines for workers' compensation or disability insurance claims

Behavioral Health

May occur in behavioral health when psychiatric or psychological conditions impact work capacity and require mental health Work Status Reports documenting cognitive and emotional functional limitations affecting employment

Individual Code References

View the standalone definition for each code in this combination.

CARC 16RARC N504

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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