Question: I applied for my NPI early, put it on my claims by the deadline, added my legacy number, and did everything by the book, but my claims are pouring in as denials from my carrier. What could I be doing wrong? Maine Subscriber Answer: The most likely reason that your carrier denied the claims is that you included the legacy number. One Part B Medicare carrier for five states (NHIC), including Maine, listed use of the legacy number as its number-one error since the May 23 NPI deadline took effect. According to a CMS press release, many clearinghouses are stripping legacy numbers off of claims, but not all clearinghouses have done so.