Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Lewis S Blumenthal, MD

Obstetrics & Gynecology Physician in Chicago, IL · enumerated 2005.

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

National Provider Identifier

1750366209

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Registry record

Entity type Individual (Type 1)

Name Lewis S Blumenthal

Credential MD

Sex Male

Practice address 55 E Washington St, Suite 3700, Chicago, IL, 60602

Phone (312) 263-5517

Fax (312) 263-5565

Enumeration date Dec 7, 2005

Last updated in NPPES Jul 8, 2007

Taxonomy & licenses

207V00000X Obstetrics & Gynecology Physician Allopathic & Osteopathic Physicians · License 036059833 (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
036059833	Medicaid	IL	-

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 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 Lewis Blumenthal?

Lewis Blumenthal is registered in NPPES with the primary taxonomy of Obstetrics & Gynecology Physician. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2007-07-08.