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William Bayer, MD

Endocrinology, Diabetes & Metabolism Physician in Carol Stream, IL · enumerated 2006.

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

National Provider Identifier

1528162898

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Registry record

Entity type Individual (Type 1)
Name William Bayer
Credential MD
Sex Male
Practice address 501 Thornhill Dr, Carol Stream, IL, 60188
Phone (630) 668-3210
Fax (630) 668-3505
Enumeration date Sep 8, 2006
Last updated in NPPES Mar 25, 2015

Taxonomy & licenses

207RE0101X Endocrinology, Diabetes & Metabolism Physician Allopathic & Osteopathic Physicians · License 036077734 (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
036077734 Medicaid IL -
036108659 Other IL MEDICAID
206147 Other IL MEDICARE GROUP PTAN
F400144099 Other IL MEDICARE INDIVIDUAL PTAN

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

How do I verify William Bayer's NPI record?
Cross-check NPI 1528162898 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.
Is NPI 1528162898 active?
Yes, as of the latest NPPES snapshot, NPI 1528162898 is active (record last updated 2015-03-25).

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2015-03-25.