How do I resolve a CO-16+N155 denial?

Verify patient's other insurance coverage: Check patient records, eligibility systems, and contact patient directly to confirm all active insurance policies including Medicare, employer coverage, or spouse's plan that may be primary or secondary to this payer Update payer's coordination of benefits records: Submit other insurance information to the payer using their designated COB update process (web portal, EDI transaction, or paper form) to ensure their records reflect current coverage before claim reprocessing File corrected claim with COB information: Submit a corrected claim (Claim Frequency Code 7) including complete other insurance details in Loop 2320 SBR segment with policy numbers, group numbers, and correct COB ordering to allow proper adjudication

835 Denial Combination

CO-16+N155

Contractual Obligation · Claim-Level Adjustment

Missing Information

What This Combination Means

Note: An informational alert accompanies this denial. The claim was denied due to missing coordination of benefits information—the payer needs documentation of other insurance coverage to process the claim correctly. This is a contractual adjustment indicating the provider failed to submit required COB data at the time of claim submission. The payer is requesting other insurance details be added to the patient's file before reprocessing.

Financial Responsibility

provider writeoff

Provider must write off the adjusted amount per contract since the billing error (missing COB information) originated from the provider's submission. Patient cannot be billed for this adjustment.

N/A

Appeal Success

7-14 days (corrected claim with COB)

Avg. Resolution

Medium

Difficulty

Appealable

Step-by-Step Resolution

Steps tailored specifically to this CO-16+N155 combination — not generic advice.

Not Appealable:This is a correctable submission error requiring a corrected claim with other insurance information, not an appealable coverage or medical necessity determination.

1
Verify patient's other insurance coverage
Check patient records, eligibility systems, and contact patient directly to confirm all active insurance policies including Medicare, employer coverage, or spouse's plan that may be primary or secondary to this payer
2
Update payer's coordination of benefits records
Submit other insurance information to the payer using their designated COB update process (web portal, EDI transaction, or paper form) to ensure their records reflect current coverage before claim reprocessing
3
File corrected claim with COB information
Submit a corrected claim (Claim Frequency Code 7) including complete other insurance details in Loop 2320 SBR segment with policy numbers, group numbers, and correct COB ordering to allow proper adjudication

Specialty Context

How CO-16+N155 typically presents across different practice types.

Dental

Dental claims often require COB for dual coverage scenarios (employer plan + spouse plan) and Medicare Advantage plans with dental riders; verify both medical and dental coverage hierarchy

Medical

Medical claims require accurate COB ordering especially for Medicare primary/secondary scenarios, workers' compensation, auto insurance, and employer group health plans with dependent coverage

Behavioral Health

Behavioral health claims may involve COB between medical plans, EAP benefits, and specialty behavioral carve-out plans; confirm which payer is primary for mental health and substance use services

Individual Code References

View the standalone definition for each code in this combination.

CARC 16 RARC N155

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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