Regex Tester & Validator

Validates a US Medicare Beneficiary Identifier (MBI), an 11-character code of digits and letters. The first character must be 1-9, alphabetic positions exclude confusable letters S, L, O, I, B, Z, and digits are required at positions 4, 7, 10, and 11. Optional hyphens after the 4th and 7th characters support formatted input like 1EG4-TE5-MK73. Useful for healthcare form validation and claims data entry checks.