Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

William D Grainger, MD

Neurology Physician in Gilbert, AZ · enumerated 2007.

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

National Provider Identifier

1003963679

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Registry record

Entity type Individual (Type 1)

Name William D Grainger

Credential MD

Sex Male

Practice address 726 N Greenfield Rd, Suite 110, Gilbert, AZ, 85234

Phone (480) 834-8885

Fax (480) 751-5724

Enumeration date Jan 4, 2007

Last updated in NPPES Jun 30, 2021

Taxonomy & licenses

2084N0400X Neurology Physician Allopathic & Osteopathic Physicians · License AZ15336 (AZ) Primary

MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

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.

Read the full guide → Validate an NPI →

Frequently asked questions

Is NPI 1003963679 active?

Yes, as of the latest NPPES snapshot, NPI 1003963679 is active (record last updated 2021-06-30).

How do I verify William Grainger's NPI record?

Cross-check NPI 1003963679 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2021-06-30.