Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. John S. Vassar, M.D.

Anesthesiology Physician in Aberdeen, SD · enumerated 2006.

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

National Provider Identifier

1144248295

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Registry record

Entity type Individual (Type 1)

Name Dr. John S. Vassar

Credential M.D.

Sex Male

Practice address 305 S State St, Aberdeen, SD, 57401

Phone (605) 622-5000

Fax (605) 622-5127

Enumeration date Jul 17, 2006

Last updated in NPPES Jul 9, 2015

Taxonomy & licenses

207L00000X Anesthesiology Physician Allopathic & Osteopathic Physicians · License 5857 (SD) 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
4992811	Other	SD	BLUE CROSS
13389	Medicaid	ND	-
25444	Other	ND	BLUE CROSS OF ND
55342	Other	SD	SANFORD
6663110511600	Other	SD	PREFERRED ONE
5857	Other	SD	DAKOTACARE
0097002	Medicaid	MT	-

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 1144248295 active?

Yes, as of the latest NPPES snapshot, NPI 1144248295 is active (record last updated 2015-07-09).

How do I verify John Vassar's NPI record?

Cross-check NPI 1144248295 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 2015-07-09.