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

William M Irvin Jr., MD

Geriatric Psychiatry Physician in Saint Louis, MO · enumerated 2006.

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

National Provider Identifier

1942392931

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Registry record

Entity type Individual (Type 1)

Name William M Irvin Jr.

Credential MD

Sex Male

Practice address Saint Louis, MO, 63141

Phone (314) 997-5208

Fax (314) 997-5368

Enumeration date Sep 28, 2006

Last updated in NPPES Dec 17, 2012

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

Taxonomy & licenses

2084P0805X Geriatric Psychiatry Physician Allopathic & Osteopathic Physicians · License 2001010868 (MO) Primary

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

Other identifiers

Identifier	Type	State	Issuer
205866304	Medicaid	MO	-
484342	Other	-	HEALTHLINK
158049	Other	-	BLUE CROSS BLUE SHIELD
1530953	Other	-	UNITED HEALTHCARE
P00049380	Other	-	RR MEDICARE

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

Is NPI 1942392931 active?

Yes, as of the latest NPPES snapshot, NPI 1942392931 is active (record last updated 2012-12-17).

How do I verify William Irvin's NPI record?

Cross-check NPI 1942392931 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 2012-12-17.