MINNEAPOLIS, May 20, 2008—As of May 23, Medicare FFS will require and send NPI-Only in ALL provider identifier fields for all HIPAA and paper transactions where a provider identifier is required. 

If you send Medicare a transaction with a Medicare legacy identifier in any of the provider fields, your claim will be rejected.    

These transactions include all electronic and paper claims (837I, 837P, NCPDP, DDE and paper CMS-1500 and UB-04), the 276/277 claims status transaction, the 270/271 eligibility transaction, 835 remittance advice and SPR paper remittance.    

If your billing software is set up to continue to send both the NPI and the legacy identifier, and your clearinghouse or billing service will not be stripping the legacy identifier from your claim as of May 23rd, the responsibility falls to the provider to send in the Medicare claim with NPI-only, i.e., NO legacy identifiers.