What do Medicare Beneficiary Identifiers (MBIs) mean for States?

If you’re a State Medicaid Agency in any state, the District of Columbia, or a U.S. territory, you need to be using Medicare Beneficiary Identifiers (MBIs) for your beneficiaries who are dually eligible for both Medicare and Medicaid.

When did states need to be ready for MBIs?

All of your systems are able to accept and are using the Health Insurance Claim Number (HICN) and/or MBI for beneficiaries who are dually eligible.

Providers, plans, beneficiaries, and other partners must use the dually eligible beneficiaries’ MBIs with us. Medicaid providers now must use MBIs in all transactions and all communications about dually eligible beneficiaries (with very few exceptions). 

For those that rely on the Medicare identifier instead of the State Medicaid ID, we'll keep providing both the HICN and MBI to State Medicaid Agencies and other COB payers through COBA eligibility response files, unless the beneficiary only ever had an MBI. In that case, we'll only provide the MBI.    

What do MBIs mean for other state entities & state partners?

If you work with beneficiaries who are dually eligible, providers, and/or health plans, you should have updated anything with the HICN, such as ID cards, beneficiary letters, training materials, or call center scripts with the MBI.

Where can states get more information about MBIs?

Read our frequently asked questions (PDF).

You can also check our Outreach & education page for resources about getting and using the MBI. 





MBI Home

Page Last Modified:
09/06/2023 04:51 PM