If a health insurance considers a physician with a given NPI as in-network, does this mean that any physician with the same NPI is also in-network?

If a health insurance plan in the United States considers a physician with a given National Provider Identifier (NPI) in-network, does this mean that any physician billing via the same NPI is also considered as in-network?

Based on my years of experience, the answer is maybe. It should be yes, but always go with maybe. In a large medical practice it might be possible for some providers in the practice to not be in-network for all insurance companies. I know of one medical office with many eye specialists that treats each provider as an individual. The central office makes the appointments, and generates the bill, but each provider is separate regarding what insurance they provide.

I have even run into the situation that a doctor split their time between two practices, in one they were in-network, in the other they were out-of-network.

I have found that the insurance company websites listing the in-network providers to be hopelessly out of date. I have found the practice website to also be out of date, or unclear. All made more confusing that some insurance companies have different tiers of providers.

The best advice is to ask when you make an appointment. Give them a scan of your card when you make the appointment, so they can look it up. The name of the insurance company isn't enough. The dental insurance we had last year had three different lists of providers, depending on what tier of insurance my company picked.