The National Provider Identifier (NPI) assigned to a provider which identifies the physician or other provider who referred the patient.
Values and websites referenced may change over time.
To search CMS’s NPI registry, you may use the following link: https://npiregistry.cms.hhs.gov/
SOURCE: T-MSIS Analytic File (TAF) Claims
From CCW Data Documentation
|Null/missing||source value is missing or unknown|