Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum
Mrs. Alyssa Rachael Westerfield, AGNP
Nurse Practitioner in Palo Alto, CA · enumerated 2018.
Data current as of Jul 13, 2026 · sourced from CMS NPPES
National Provider Identifier
1427528710
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Registry record
Entity type Individual (Type 1)
Name Mrs. Alyssa Rachael Westerfield
Credential AGNP
Sex Female
Practice address 900 Blake Wilbur Dr Fl 3, Palo Alto, CA, 94304
Phone (650) 498-6000
Enumeration date Nov 29, 2018
Last updated in NPPES Feb 18, 2019
Taxonomy & licenses
363L00000X Nurse Practitioner Physician Assistants & Advanced Practice Nursing Providers · License 95010407 (CA) Primary
What is an NPI number?
A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.
Frequently asked questions
What specialty is Alyssa Westerfield?
Alyssa Westerfield is registered in NPPES with the primary taxonomy of Nurse Practitioner. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.
Is this the official NPI registry?
No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.
Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2019-02-18.