Three-Character Prefix on Member ID Cards

Blue Cross and Blue Shield member identification numbers (ID) usually begin with a three-character prefix. Previously, the prefixes included only letters. As of April 2018, to ensure we have enough prefixes to support our current and future business needs, the Blue Cross and Blue Shield Association has determined that the prefixes can now be alphanumeric.

Quick reminders:

  • Three-character member ID prefixes may now have both letters and numbers.
  • Cards that have prefixes with letters-only are still valid.
  • The three-character prefix is always followed by the rest of the member’s ID number.
  • Include the entire member ID number, with the prefix, on all correspondence and claims.
  • Do not omit, randomly select or substitute a different three-character prefix.
  • If a member’s ID number does not have a three-character prefix, make sure you request their most current identification card.
  • Some Blue Cross and Blue Shield member ID prefixes may have less than three characters. Federal Employee Program® members, for example, have a single-letter prefix.

Be sure to obtain eligibility and benefits to confirm membership (including the correct ID number), verify the member’s coverage and determine if you are in-network or out-of-network for the member’s plan before rendering services.