What is an NPI, and whose is it?

An NPI is a national provider identifier: a ten digit number that identifies a healthcare provider to every payer in the country.

There are two kinds, and a claim usually carries both.

• A group NPI belongs to the practice, and it is the number a payer knows that practice by for billing.
• An individual NPI belongs to one doctor, and it names who actually provided the care.

Remember this one rule, because new billers get it wrong and it is expensive: NPIs belong to the doctors and the practices you bill for, never to your own billing company. Your company is the one doing the work. The provider is the one the payer pays.

The NPI is also the number an enrollment introduces to a payer. When you enroll a group, what you are really doing is asking the payer to recognize that NPI for one kind of transaction.

Alongside the NPI, a practice has a tax ID, which is the number a payer knows it by for money. It is either an EIN or an SSN, and you tell the system which. See What is a provider group?.