Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Mark L Switzer, M.D.

Hospitalist Physician in Bolingbrook, IL · enumerated 2006.

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

National Provider Identifier

1336181395

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Registry record

Entity type Individual (Type 1)

Name Dr. Mark L Switzer

Credential M.D.

Sex Male

Practice address 1000 Remington Blvd, Suite 200, Bolingbrook, IL, 60440

Phone (630) 312-7755

Fax (630) 856-9933

Enumeration date Jun 12, 2006

Last updated in NPPES Mar 6, 2017

Taxonomy & licenses

208M00000X Hospitalist Physician Allopathic & Osteopathic Physicians · License 036102478 (IL) Primary

208000000X Pediatrics Physician Allopathic & Osteopathic Physicians · License 036102478 (IL) Secondary

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 036102478 (IL) Secondary

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

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 Mark Switzer?

Mark Switzer is registered in NPPES with the primary taxonomy of Hospitalist 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 2017-03-06.