Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Dr. Nathaniel Joseph Leonardi, DO

Nephrology Physician in Chicago, IL · enumerated 2020.

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

National Provider Identifier

1427685445

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Registry record

Entity type Individual (Type 1)

Name Dr. Nathaniel Joseph Leonardi

Credential DO

Sex Male

Practice address 1725 W Harrison St Ste 161, Chicago, IL, 60612

Phone (312) 942-4252

Enumeration date Mar 27, 2020

Last updated in NPPES May 4, 2026

Taxonomy & licenses

207RN0300X Nephrology Physician Allopathic & Osteopathic Physicians · License 036.179518 (IL) Primary

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

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 1427685445 active?

Yes, as of the latest NPPES snapshot, NPI 1427685445 is active (record last updated 2026-05-04).

How do I verify Nathaniel Leonardi's NPI record?

Cross-check NPI 1427685445 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 2026-05-04.