Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Mark Francis Grenquist, DO

Internal Medicine Physician in Chelsea, MI · enumerated 2006.

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

National Provider Identifier

1942300454

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Registry record

Entity type Individual (Type 1)

Name Dr. Mark Francis Grenquist

Credential DO

Sex Male

Practice address 775 S Main St, Chelsea, MI, 48118

Phone (734) 593-6000

Enumeration date Sep 24, 2006

Last updated in NPPES Sep 6, 2016

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License 5101014936 (MI) Primary

208M00000X Hospitalist Physician Allopathic & Osteopathic Physicians · License 5101014936 (MI) Secondary

DO · Doctor of Osteopathic Medicine: A fully licensed physician trained in osteopathic medical schools, with the same practice rights as an MD. About the DO credential

Other identifiers

Identifier	Type	State	Issuer
1942300454	Medicaid	MI	-
1417961137	Other	MI	BCBSM - BRONSON BATTLE CREEK
5331090	Other	MI	BCBS INDIVIDUAL PIN
4631106	Medicaid	MI	-

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 Mark Grenquist's NPI record?

Cross-check NPI 1942300454 against the official CMS registry at npiregistry.cms.hhs.gov. This page mirrors the same public NPPES data with a monthly snapshot.

Is NPI 1942300454 active?

Yes, as of the latest NPPES snapshot, NPI 1942300454 is active (record last updated 2016-09-06).

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2016-09-06.