NPI Portal NPI Lookup & Verification

Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Ms. Gwendolyn Williams Isler, MS RD LD

Registered Dietitian in Winchester, VA · enumerated 2006.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1801996566

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Registry record

Entity type Individual (Type 1)
Name Ms. Gwendolyn Williams Isler
Credential MS RD LD
Sex Female
Practice address Winchester, VA, 22601
Phone (540) 678-0600
Enumeration date Sep 23, 2006
Last updated in NPPES Feb 6, 2015

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

133V00000X Registered Dietitian Dietary & Nutritional Service Providers 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.

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Frequently asked questions

What specialty is Gwendolyn Isler?
Gwendolyn Isler is registered in NPPES with the primary taxonomy of Registered Dietitian. 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.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2015-02-06.