Overview#

Medicare Beneficiary Identifier (MBI or Medicare Number) is a Unique Identifier, a Unique Health IDentifier for Patients enrolled in Centers for Medicare and Medicaid Services (CMS) and is considered Personally Identifiable Information (PII)

In April 2018, Centers for Medicare and Medicaid Services began mailing out new Medicare cards with new ID numbers to all beneficiaries. Previous cards had ID numbers containing beneficiaries' Social Security Numbers; the new ID numbers are randomly generated and not tied to any other Personally Identifiable Information.

Medicare Beneficiary Identifier prefixes and suffixes are not used with the non-SSN style Identifiers

Medicare Beneficiary Identifier format#

The MBI will contain letters and numbers. Here’s an example: 1EG4-TE5-MK73

• The MBI’s 2nd, 5th, 8th, and 9th characters will always be a letter
• Characters 1, 4, 7, 10, and 11 will always be a number
• The 3rd and 6th characters will be a letter or a number

The dashes aren’t used as part of the MBI. They won’t be entered into computer systems or used in file formats.

Alphabetic Character (A...Z) Letters that might be confusing are Excluded (S, L, O, I, B, Z)

• Position 1 – numeric values 1 thru 9
• Position 2 – alphabetic values A thru Z (minus S, L, O, I, B, Z)
• Position 3 – alpha-numeric values 0 thru 9 and A thru Z (minus S, L, O, I, B, Z)
• Position 4 – numeric values 0 thru 9
• Position 5 – alphabetic values A thru Z (minus S, L, O, I, B, Z)
• Position 6 – alpha-numeric values 0 thru 9 and A thru Z (minus S, L, O, I, B, Z)
• Position 7 – numeric values 0 thru 9
• Position 8 – alphabetic values A thru Z (minus S, L, O, I, B, Z)
• Position 9 – alphabetic values A thru Z (minus S, L, O, I, B, Z)
• Position 10 – numeric values 0 thru 9
• Position 11 – numeric values 0 thru 9

More Information#

There might be more information for this subject on one of the following:

• MBI
• Medicare Number
• Unique Health IDentifier

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• [#1] - Understanding the Medicare Beneficiary Identifier (MBI) Format - based on information obtained 2019-09-26
• [#2] - Historic Suffix Codes - based on information obtained 2019-09-26