To protect the privacy of Medicare recipients and prevent fraudulent use of social security numbers (SSN), a new, unique 11-character Medicare Beneficiary Identifier (MBI) is replacing the SSN-based Health Insurance Claim Number (HICN) for Medicare transactions such as billing, eligibility status, and claim submissions. The MBI does not change Medicare benefits.

What’s Behind the Change?

The Centers for Medicare & Medicaid Services’ (CMS) New Medicare Card Project, formerly the SSN Removal Initiative (SSNRI), mandated this change under the Medicare Access and CHIP Reauthorization Act (MACRA) of 2015. CMS must discontinue using all SSN-based HICN identifiers; CMS reissued all Medicare cards with a new MBI as of April 2019. The primary goal behind the initiative is to help combat identity theft and illegal use of Medicare benefits.

CMS Implementation Timeline

In April 2018, the CMS started mailing out new cards to meet the required deadline for the replacement of all cards by April 2019. These new cards have a new design, list the new Medicare number (MBI), and omit gender and signatures.

The 21-month transition period for the SSNRI began in April 2018 and will extend until December 31, 2019, to ensure that all processes and systems are modified to accept and transmit MBIs. Even though all systems need to be able to accept the new MBI format starting April 2018, during this transition period, healthcare providers will be allowed to use either the HICN or MBI to exchange data with the CMS.

Starting January 1, 2020, MBI’s must be used on all claims, with a few exceptions. (Exceptions may include appeals and retrospective adjustments.)

Finding the MBI

All Medicare beneficiaries should now have their new card. So, if they report not yet receiving one, they need to contact Medicare and verify that the address they have on file matches the patients’ address.

In addition to their new card having their MBI on it, beneficiaries can also access their MBI via MyMedicare.gov.

Providers can use the Medicare Administrative Contractors’ (MAC) secure MBI look-up tool to find a patient’s MBI. Also, Medicare began returning both the HICN and the MBI on every remittance advice for claims submitted with a valid and active HICN in October 2018 and will continue to do so through December 31, 2019.

What Do MBIs Look Like?

MBIs are 11-characters in length and occupy the same field in Medicare transactions. However, MBIs are distinguishable from HICNs, comprised of randomly assigned numbers and uppercase letters (excluding letters at risk for being interpreted as numbers S, L, O, I, B, Z) with no embedded meaning. As shown in CMS’ illustration Understanding the MBI Format