NPI

The NPI (National Provider Identifier) is a unique 10-digit number assigned to every individual healthcare provider and healthcare organization in the United States. It is required on every claim — without a valid, active NPI, claims are rejected at the clearinghouse layer before they reach the payer. There are two NPI types: Type 1 NPIs are assigned to individual providers (physicians, NPs, PAs, therapists, etc.) and Type 2 NPIs are assigned to organizations (group practices, hospitals, ambulatory surgery centers, lab companies). A claim typically requires multiple NPIs: the rendering provider NPI (who actually performed the service), the billing provider NPI (the entity submitting the claim and receiving payment, often the group), and sometimes a referring provider NPI (when the service requires referral). Mismatched NPIs are one of the most common triggers for CO-16 missing-information denials — particularly when the rendering provider's taxonomy code on the claim does not match what is registered in NPPES (the federal NPI registry) and the payer's enrollment file. NPIs are obtained free through NPPES Online, are not subject to expiration, and stay with the provider for life. New providers joining a practice need their NPI deactivated from prior employers' enrollment files and re-linked to the new group's billing NPI for every payer relationship — this is the single most common credentialing-related billing failure for new hires.