Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Nicholas L Hartog, M.D.

Allergy & Immunology Physician in Grand Rapids, MI · enumerated 2011.

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

National Provider Identifier

1669766325

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Registry record

Entity type Individual (Type 1)

Name Dr. Nicholas L Hartog

Credential M.D.

Sex Male

Practice address 3271 Clear Vista Ct Ne, Grand Rapids, MI, 49525

Phone (616) 267-7125

Fax (616) 267-9593

Enumeration date May 30, 2011

Last updated in NPPES Mar 17, 2021

Taxonomy & licenses

207K00000X Allergy & Immunology Physician Allopathic & Osteopathic Physicians · License 2014010402 (MO) Secondary

207K00000X Allergy & Immunology Physician Allopathic & Osteopathic Physicians · License 4301108955 (MI) Primary

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License R-9168 (IA) 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 NPI 1669766325 active?

Yes, as of the latest NPPES snapshot, NPI 1669766325 is active (record last updated 2021-03-17).

How do I verify Nicholas Hartog's NPI record?

Cross-check NPI 1669766325 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 2021-03-17.