The MBI has 11 characters, like the Health Insurance Claim Number (HICN), which can have up to 11. Each MBI is randomly generated which makes MBIs different than HICNs, which are based on the SSNs of Medicare recipients. MBI characters are “non-intelligent” so they don’t have any hidden or special meaning.
As a reminder, each person with Medicare will get his/her own randomly generated MBI. Spouses or dependents who may have had similar HICNs will each get their own different MBIs.
The Railroad Retirement Board (RRB) also mailed new Medicare cards with MBIs. The RRB logo will be in the upper left corner and “Railroad Retirement Board” at the bottom, but you can’t tell from looking at the MBI if your patient is eligible for Medicare because they’re a railroad retiree. You’ll be able to identify them by the RRB logo on their card, and CMS will return a “Railroad Retirement Medicare Beneficiary” message on the Fee-For-Service (FFS) MBI eligibility transaction response.
CMS will end the MBI transition period on Dec. 31, 2019, and the MBI must be used for all traditional Medicare transactions.
Starting on Jan. 1, 2020, regardless of the date of service, Medicare transactions will be rejected if the MBI is not used. There are a few Medicare plan exceptions, including appeals; some adjustments (Drug Data Processing, Risk Adjustment Processing and Encounter Data); and Retrospective Reporting.
CMS suggests getting your MBIs for patients in one of three ways:
Ask the Medicare patient
Use your MAC’s secure MBI look-up tool. You must sign up in the CMS portal to use the tool
Check remittance advice – the MBI will be returned on claims with valid and active HICNs through the end of 2019
To learn more, visit CMS at: