Are You Using the New
Medicare Beneficiary Identifier (MBI)?

T he Centers for Medicare & Medicaid Services (CMS) has replaced the Social Security Number-based Health Insurance Claim Number (HICN) with the MBI. The MBI will be used for transactions such as billing, eligibility status, and claim status. The MBI does not change a beneficiary’s Medicare benefits.

Each MBI is randomly generated and comprised of eleven characters to include numbers 0-9 and upper-case letters A-Z (except for S, L, O, I, B, and Z to avoid confusion). 

During the transition period through December 31, 2019, either the new MBI or the old HICN will be accepted on transactions with the CMS. Starting January 1, 2020, you must use the new MBI on claims regardless of what date the service was provided to the beneficiary. According to the CMS, 75% of the claims received through the end of June 2019 were received with the new MBIs.

Providers can take the following actions to obtain the new MBI for beneficiaries:

  1. Ask the Medicare beneficiary for their new MBI.
  2. Use the Medicare Administrative Contractors (MACs) secure MBI look-up tool.
  3. Check the remittance advice – the MACs are returning the MBIs on every remittance advice.
For more information or assistance with the topic on the new Medicare Beneficiary Identifier, please contact Rick Snyder, Billing and Reimbursement Consultant, .