CommonContractual Obligation (CO)Coordination of Benefits

CO-109: Claim not covered by this payer

The claim has been denied because this payer is not responsible for coverage. The service should be billed to a different insurance company. This often occurs in coordination of benefits situations where the wrong payer was billed as primary.

Common Causes

  • Wrong payer billed -- patient has multiple insurance plans
  • Coordination of benefits issue -- this payer is secondary, not primary
  • Patient's coverage is through a different subsidiary or plan
  • Workers' compensation or auto insurance should be primary for this claim
  • Medicare Secondary Payer rules apply

How to Resolve CO-109

  1. 1Contact the patient to verify all active insurance coverage and determine primary/secondary order
  2. 2If COB is the issue, bill the correct primary payer first
  3. 3Once the primary payer has paid, submit to the secondary with the primary EOB
  4. 4If this payer is primary but denying, appeal with coordination of benefits documentation

How to Prevent CO-109 Denials

  • Collect all insurance information including secondary/tertiary at registration
  • Run eligibility verification that includes COB information
  • Ask about work-related injuries and auto accidents to identify correct primary payer
  • Verify payer order using birthday rule or other COB determination guidelines

Related Denial Codes

CO-22Moderate

Care may be covered under a capitation or managed care plan

CO-27Common

Expenses incurred after coverage terminated

CO-96Common

Non-covered charge(s)

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