is about CRID centrally registered identifier care site National Provider Identifier http://ohdsi.github.io/CommonDataModel/cdm54.html#PERSON National Providier Number http://purl.obolibrary.org/obo/NCIT_C54633 Oliver He, Long Tran A centrally registered identifier that refers to the National Provider Number issued to health care providers in the US by the Centers for Medicare and Medicaid Services (CMS). NPI is assigned for use in all administrative and financial transactions specified by HIPAA.