Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. William J Mackin, M.D.

Cardiovascular Disease Physician in Geneva, IL · enumerated 2005.

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

National Provider Identifier

1215924949

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Registry record

Entity type Individual (Type 1)

Name Dr. William J Mackin

Credential M.D.

Sex Male

Practice address 351 Delnor Dr, Suite 100, Geneva, IL, 60134

Phone (630) 232-0280

Fax (630) 232-3895

Enumeration date Sep 27, 2005

Last updated in NPPES Apr 20, 2025

Taxonomy & licenses

207RC0000X Cardiovascular Disease Physician Allopathic & Osteopathic Physicians · License 4301053298 (MI) Secondary

207RC0000X Cardiovascular Disease Physician Allopathic & Osteopathic Physicians · License MED-PHYS-COM-143864 (MT) Secondary

207RI0011X Interventional Cardiology Physician Allopathic & Osteopathic Physicians · License 036077645 (IL) Secondary

207RI0011X Interventional Cardiology Physician Allopathic & Osteopathic Physicians · License 4761-320 (WI) Secondary

207RC0000X Cardiovascular Disease Physician Allopathic & Osteopathic Physicians · License 036077645 (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
100298082	Medicaid	WI	-
206147058	Other	IL	MEDICARE PTAN (INDIVIDUAL)
206147	Other	IL	MEDICARE PTAN (GROUP)
036077645	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

Is NPI 1215924949 active?

Yes, as of the latest NPPES snapshot, NPI 1215924949 is active (record last updated 2025-04-20).

How do I verify William Mackin's NPI record?

Cross-check NPI 1215924949 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2025-04-20.