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Mainstay Clinics Inc

Nurse Practitioner in Libertyville, IL · enumerated 2018 · authorized official Alexander Jarosz, Officer.

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

National Provider Identifier

1134622053

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Registry record

Entity type Organization (Type 2)
Legal business name Mainstay Clinics Inc
Practice address 333 Peterson Rd Ste 240, Libertyville, IL, 60048
Phone (224) 864-2124
Fax (224) 864-2178
Enumeration date Mar 16, 2018
Last updated in NPPES Aug 29, 2025

Taxonomy & classification

363L00000X Nurse Practitioner Physician Assistants & Advanced Practice Nursing Providers · License 209009332 (IL) Primary

Authorized official

Name Alexander Jarosz
Title Officer
Phone (224) 717-0447

Other identifiers

Identifier Type State Issuer
2011015746 Other IL ANCC
338829946001 Medicaid IL -
363L00000X Other IL TAXONOMY

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 current is this record?
Data comes from the CMS NPPES public dissemination file; this record was last updated in NPPES on 2025-08-29. Verify at npiregistry.cms.hhs.gov.
Where is Mainstay Clinics Inc located?
The practice location on file with NPPES is in Libertyville, IL.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2025-08-29.