Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Jason Shaun Day, MD

Vascular Neurology Physician in Oak Lawn, IL · enumerated 2008.

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

National Provider Identifier

1427205038

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Registry record

Entity type Individual (Type 1)

Name Dr. Jason Shaun Day

Credential MD

Sex Male

Practice address 4440 W 95th St, Oak Lawn, IL, 60453

Phone (303) 436-2727

Enumeration date Aug 26, 2008

Last updated in NPPES Jan 19, 2026

Taxonomy & licenses

2084V0102X Vascular Neurology Physician Allopathic & Osteopathic Physicians · License ME120414 (FL) Secondary

2084N0400X Neurology Physician Allopathic & Osteopathic Physicians · License ME120414 (FL) Secondary

2084V0102X Vascular Neurology Physician Allopathic & Osteopathic Physicians · License 036-172471 (IL) 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
013517400	Medicaid	FL	-
100387633	Medicaid	WI	-
P01389312	Other	FL	RAILROAD 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

What specialty is Jason Day?

Jason Day is registered in NPPES with the primary taxonomy of Vascular Neurology Physician. 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 2026-01-19.