As you know, beginning March 1 of this year, claims without a National Provider Identifier (NPI) number in the primary provider field and claims with only a Medicare legacy number in the primary provider field are being rejected

and not reimbursed. Effective May 23, 2008, only the NPI will be accepted for all HIPAA electronic transactions, paper claims (UB-04 and CMS-1500), and Standard Paper Remittance (SPR) advices. This means that, in less than two

months, you should no longer report Medicare billing numbers in primary or secondary provider fields if you want the claims accepted, processed, and paid.

See article for more information.