Coding Cues: New NPI mandate

CMS recently alerted us that we need to start billing Medicare using our National Provider Identifier. We're already doing this because we've been under the impression that this has been a requirement for some time. Can you clarify?

Until March 1 of this year, use of the NPI was encouraged but not mandated. Since then, Medicare fee-for-service claims must include an NPI in the primary provider fields (billing, pay-to provider, and rendering provider). You may submit NPI/legacy pairs in these provider fields or submit only your NPI, but if the NPI isn't included, the claim will be rejected. There's no such mandate for the secondary provider fields.