CMS’s transition to Medicare Beneficiary Identifiers (MBI) numbers is coming to a close at the end of the month. CMS has been issuing new Medicare cards with MBI numbers since 2018 in order to replace their old identifiers, which were called Health Insurance Claim Number (HICN).

An MBI number is an 11 digit combination of numbers and letters which better protects from identity fraud as the HICN format contained a beneficiary’s social security number.

CMS completed issuing the updated cards as of April but has been allowing Medicare claims to be submitted with either the MBI or Health Insurance Claim Number (HICN).

Beginning January 1st, 2020, any claims submitted to Medicare without the MBI number will be denied.

In a recent update from CMS, 86% of Medicare claims are currently being submitted with the correct MBI number. While a majority of Medicare beneficiaries are providing the correct information, some stragglers are still using their old HICN. As a result, denials could potentially increase starting in January – so we recommend that you do everything you can to make sure the correct MBI information is being requested/provided.

Click here for more information and resources on the transition to MBI numbers.


Kayley Jaquet

Manager of Regulatory Affairs