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Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 60 days.

MACKENZIE ANNE STEFFEN
NPI 1699605642
Physician Assistant - Medical in Williamsville, NY

Active since May 21, 2026
295 ESSJAY RD, WILLIAMSVILLE, NY 14221(716) 630-1151(716) 250-5997 Get Directions Write a Review

NPPES record last updated: September 29, 2026. Verified against the NPPES registry weekly; last sync: October 04, 2026.

Record update history: Sep 29, 2026, May 21, 2026 (2 updates tracked since 2026).

About Mackenzie Anne Steffen NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

MACKENZIE ANNE STEFFEN (NPI 1699605642) is an individual medical provider in Williamsville, New York, licensed in New York (036231) and active in the NPI registry since May 2026. She maintains 4 additional practice locations.

NPPES Registry Identity

NPI1699605642
Entity TypeIndividualFemale
Primary Taxonomy363AM0700X
Provider Legal NameMACKENZIE ANNE STEFFEN
Location Address295 ESSJAY RDWilliamsville, NY 14221-5795
Mailing Address425 Essjay Rd Ste 170Williamsville, NY 14221-8235 · (716) 630-1219 · Fax (716) 817-1726
Phone(716) 630-1151
Fax(716) 250-5997
Sole ProprietorNo
Enumeration DateMay 21, 2026
Last NPPES UpdateSeptember 29, 20262 updates tracked since enumeration
NPPES CertifiedSeptember 29, 2026
✔ NPI 1699605642 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyPhysician Assistant · MedicalPhysician Assistants & Advanced Practice Nursing Providers
Taxonomy Code363AM0700X
License✔ Licensed in NY · 036231
295 ESSJAY RD, Williamsville, NY 14221
Open in Google Maps ↗

Secondary Practice Locations 4

Location 1325 Essjay RdWilliamsville, NY 14221-8243 · Phone (716) 630-1000 · Fax (716) 250-5997
Location 23900 N Buffalo StOrchard Park, NY 14127-1842 · Phone (716) 630-1000 · Fax (716) 250-5997
Location 385 High StBuffalo, NY 14203-1194 · Phone (716) 630-1000 · Fax (716) 250-5997
Location 46950 S Transit RdLockport, NY 14094-6333 · Phone (716) 630-1000 · Fax (716) 250-5997

Other Providers at the Same Location NPPES 20

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

YIJUN CHENG M.D.
Internal Medicine (Hematology & Oncology)
295 ESSJAY RD
WILLIAMSVILLE, NY 14221
Erie County (716) 630-1048
DR. PHILIP A SWIANTEK MD
Urology
295 ESSJAY RD
WILLIAMSVILLE, NY 14221
Erie County (716) 630-1050
DR. ROBERT M ZIELINSKI MD
Internal Medicine (Hematology & Oncology)
295 ESSJAY RD
WILLIAMSVILLE, NY 14221
Erie County (716) 630-1059
MRS. TERRA GALVANO DNP
Nurse Practitioner
295 ESSJAY RD
WILLIAMSVILLE, NY 14221
Erie County (716) 630-1000
JEANINE FLEMING SCHNELL NP
Nurse Practitioner (Adult Health)
295 ESSJAY RD
WILLIAMSVILLE, NY 14221
Erie County (716) 630-1152
DR. MARY K MCGORRAY MD
Internal Medicine
295 ESSJAY RD
WILLIAMSVILLE, NY 14221
Erie County (716) 630-1159
MRS. JILL ELLEN HESS PA
Physician Assistant
295 ESSJAY RD
WILLIAMSVILLE, NY 14221
Erie County (716) 630-1050
RENEE A ANDREEFF PHYSICIAN ASSISTANT
Physician Assistant
295 ESSJAY RD
WILLIAMSVILLE, NY 14221
Erie County (716) 630-1000

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Mackenzie Steffen's NPI number?

The NPI number for Mackenzie Steffen is 1699605642. It was assigned to this individual provider in the NPPES registry on May 21, 2026.

Where is Mackenzie Steffen located?

Mackenzie Steffen practices at 295 Essjay Rd, Williamsville, NY 14221. The listed phone number is (716) 630-1151.

What is Mackenzie Steffen's specialty?

The primary specialty registered for this NPI is Physician Assistant, specializing in Medical, with taxonomy code 363AM0700X.

When was this NPI record last updated?

The NPPES record for Mackenzie Steffen was last updated on September 29, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 7 days ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.