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Medicare Beneficiary Identifier Monthly Tip

Are you receiving claim rejections because of an invalid beneficiary identifier? It could be that you are using the wrong characters on the MBI.

The new Medicare number will not include the letters S, L, O, I, B and Z because they look too much like numbers.


  • The number zero (0), not the letter O.
  • The number eight (8), not the letter B.
  • The number two (2), not the letter Z.

As a reminder, the MBI is required on all claims submitted to MACs on and after 1/1/2020. Claims received with the HICN after this date may be rejected.

Posted 8/14/2019

Last Modified: 8/14/19
Medicare Beneficiary Identifier Monthly Tip
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