835 Denial Combination

CO-16+N257

CO

Contractual Obligation · Service-Line Level Adjustment

Missing Information

What This Combination Means

The claim was denied because the billing provider's primary identifier (typically the NPI in loop 2010AA) is missing, incomplete, or invalid on the submitted claim. This is a correctable billing error where the payer cannot process the claim without proper identification of the billing entity. The provider must correct the identifier and resubmit.

Financial Responsibility

provider writeoff

The provider must write off this amount as a contractual adjustment and cannot bill the patient. Once the billing provider identifier is corrected and the claim is resubmitted, the claim may be processed for payment.

N/A

Appeal Success

5-10 business days (corrected claim)

Avg. Resolution

Medium

Difficulty

No

Appealable

Step-by-Step Resolution

Steps tailored specifically to this CO-16+N257 combination — not generic advice.

Not Appealable:This is a correctable submission error requiring claim correction and resubmission rather than appeal.
  1. 1

    Verify the billing provider NPI in loop 2010AA of the original claim submission

    The payer has identified the primary identifier as missing, incomplete, or invalid; confirm what was transmitted versus what is on file with the payer

  2. 2

    Obtain or confirm the correct billing provider NPI and ensure it matches payer enrollment records

    Validate the NPI is active in NPPES and enrolled with this specific payer; mismatches between billing systems and payer records are common causes

  3. 3

    Submit a corrected claim with the accurate billing provider primary identifier in the appropriate loop/segment

    Use claim frequency code 7 and ensure the billing provider NPI in loop 2010AA is complete and matches the enrolled billing entity

Specialty Context

How CO-16+N257 typically presents across different practice types.

Dental

Verify the billing dentist or group practice NPI is correctly entered; dental claims may have both rendering and billing provider identifiers that must align with payer enrollment

Medical

Common in facility and group practice billing where the billing provider TIN/NPI combination must match payer enrollment; ensure the billing entity NPI (not rendering provider NPI) is in the correct field

Behavioral Health

Frequent when billing through group practices or clinics; ensure the billing entity NPI matches the enrolled organization and not the individual rendering therapist or counselor

Individual Code References

View the standalone definition for each code in this combination.

CARC 16RARC N257

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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