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

Q: 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.

Q: What is Mackenzie Steffen's specialty?

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

Q: 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 28 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.

Active since May 21, 2026PECOS Enrolled

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 25, 2026.

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

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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 is enrolled in Medicare PECOS and 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

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Secondary Practice Locations 4

Location 16950 S Transit RdLockport, NY 14094-6333 · 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 3325 Essjay RdWilliamsville, NY 14221-8243 · Phone (716) 630-1000 · Fax (716) 250-5997

Location 485 High StBuffalo, NY 14203-1194 · Phone (716) 630-1000 · Fax (716) 250-5997

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, and ordering and referring status from the CMS PECOS system.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Mackenzie Anne Steffen is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

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)