Provider Responsibility Regarding Third Party Liability and Secondary Billing

In a previous notice, the Office of MaineCare Services (OMS) reminded providers of your responsibilities regarding third -party liability and secondary billing. Pursuant to MaineCare Benefits Manual (MBM) Ch. I Section 1.07-3(B), MaineCare is the payor of last resort. OMS announced that we will update the billing and claims system requirements to accurately reflect the provider’s obligation to bill primary insurance when other coverage is available.

Effective August 10, 2026, our claims system will no longer treat most Current Procedural Terminology (CPT) and Healthcare Common Procedure Coding System (HCPCS) codes as exempt from billing the primary commercial carrier. In accordance with MBM Ch. I Section 1.07: Third Party Liability, providers must seek payment from the primary carrier before billing MaineCare for all claims for these services for members with primary coverage, even when:

  • the billing codes for same services vary between payors; and
  • the primary payor’s service coverage applies only to a portion of the MaineCare defined service. For example, this applies when the MaineCare service is more comprehensive than the primary payor’s coverage.

MaineCare also recognizes that many provider types that were previously unable to enroll in Medicare can now enroll and bill Medicare as the primary payor for services delivered to members dually eligible for Medicare and Medicaid. Providers eligible to enroll with Medicare to deliver Medicare reimbursable services must do so to receive MaineCare reimbursement as a secondary payor.

MaineCare’s claims system will accept an Explanation of Benefits (EOB) with primary dollars attached even if the billing codes differ. The system will process secondary claims as long as the provider, member, dates of service, and billed charges match. Providers must use the most specific code possible to maintain billing integrity and to comply with correct claim submission procedures.

Please monitor MaineCare e-messages for future communications on this topic as continued reviews and necessary system changes occur. We appreciate your efforts to preserve MaineCare funding and ensure compliance with these requirements.

For questions, please contact your Provider Relations Specialist.