Browse this site http://www.whatismedicalinsurancebilling.org/2010/06/bcbs-alpha-prefix-list-and-claim.html for more information on BCBS alpha prefix list. Its often confused that BCBS have lot of prefixes and where to contact. However we have some guide to follow, using prefixes we could find the state of the BCBS and contact phone number to proceed further. Use find (Ctrl + F) and enter the prefix to find the BCBS state. A member’s ID number includes the alpha prefix in the first three positions and all subsequent characters ‒ between 6 and 14 numbers or letters ‒ up to 17 characters total.more