Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

William Arthur Grass, ARNP

Critical Care Medicine Nurse Practitioner in Creve Coeur, MO · enumerated 2005 · practices at Washington University.

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

National Provider Identifier

1407854383

Verified

See something wrong? Report a correction

Registry record

Entity type Individual (Type 1)

Name William Arthur Grass

Credential ARNP

Sex Male

Practice address 10 Barnes West Dr, Creve Coeur, MO, 63141

Phone (314) 996-8270

Enumeration date Jul 13, 2005

Last updated in NPPES Jul 30, 2025

Taxonomy & licenses

363LC0200X Critical Care Medicine Nurse Practitioner Physician Assistants & Advanced Practice Nursing Providers · License ARNP9207097 (FL) Primary

Other identifiers

Identifier	Type	State	Issuer
Y061EY	Other	FL	MEDICARE GTBA REASSIGN
308331400	Medicaid	FL	-

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 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.

What specialty is William Grass?

William Grass is registered in NPPES with the primary taxonomy of Critical Care Medicine Nurse Practitioner. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

Other providers at this practice address

Browse all →

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2025-07-30.