Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Tom Klein, MD

Internal Medicine Physician in Riverwoods, IL · enumerated 2006.

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

National Provider Identifier

1326094194

Verified

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Registry record

Entity type Individual (Type 1)

Name Tom Klein

Credential MD

Sex Male

Practice address 1105 Milwaukee Ave, Riverwoods, IL, 60015

Phone (847) 325-5110

Fax (847) 325-5114

Enumeration date May 25, 2006

Last updated in NPPES Dec 3, 2024

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 4193020 (WI) Secondary

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 036065537 (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
4193020	Other	WI	WISCONSIN LISC#
036065537	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.

Read the full guide → Validate an NPI →

Frequently asked questions

What specialty is Tom Klein?

Tom Klein is registered in NPPES with the primary taxonomy of Internal Medicine 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 2024-12-03.