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NASSAU IMMED MED CARE PLLC
NPI 1255429254
Internal Medicine in Williston Park, NY

Active since October 11, 2006
465 WILLIS AVE, WILLISTON PARK, NY 11596(516) 294-3535(516) 294-6451 Get Directions Write a Review

NPPES record last updated: March 17, 2008. Verified against the NPPES registry weekly; last sync: November 01, 2026.

About Nassau Immed Med Care Pllc NPPES

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

NASSAU IMMED MED CARE PLLC (NPI 1255429254) is a healthcare organization registered as an internal medicine in Williston Park, New York and active in the NPI registry since October 2006. The organization lists Susan P. Welgrin, Member, as its authorized official.

NPPES Registry Identity

NPI1255429254
Entity TypeOrganization
Primary Taxonomy207R00000X
Legal Business NameNASSAU IMMED MED CARE PLLC
Location Address465 WILLIS AVEWilliston Park, NY 11596-1724
Mailing Address465 Willis AveWilliston Park, NY 11596-1724 · (516) 294-3535 · Fax (516) 294-6451
Phone(516) 294-3535
Fax(516) 294-6451
Organization SubpartNo
Authorized OfficialSusan P. WelgrinMember · (516) 294-3535
Enumeration DateOctober 11, 2006
Last NPPES UpdateMarch 17, 2008
✔ NPI 1255429254 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207R00000X
License✔ Licensed in NY · 187440
Definition
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.
465 WILLIS AVE, Williston Park, NY 11596
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Other Identifiers 1

Medicare ID-Type UnspecifiedWLW201NY

Group Practice 1

Group TaxonomyThis provdier is a business group of one or more individual practitioners, all of who practice with the same area of specialization.193400000X SINGLE SPECIALTY GROUP

Medicare Participation & PECOS CMS

Medicare enrollment and the clinicians who bill Medicare through this organization, from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Nassau Immed Med Care Pllc is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Clinicians Billing Medicare Through This Organization

Medicare enrollment records show 1 clinician reassigns Medicare billing to Nassau Immed Med Care PLLC, which bills Medicare for the services this clinician delivers.

Clinician (1)

Susan Welgrin, M.D.
Internal Medicine
NPI 1518970888
465 WILLIS AVE
Williston Park, NY 11596
(516) 294-3535
✔ PECOS✔ Accepts MedicareSame address

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

CLIA Laboratory Certificates CMS CLIA

Laboratory certificates issued under the Clinical Laboratory Improvement Amendments (CLIA) program, which sets federal quality standards for human laboratory testing in the United States. There is no official CMS crosswalk between CLIA and NPI numbers; these certificates are associated with this NPI by matching facility names, locations and phone numbers in the CMS CLIA registry.

Certificate of Compliance 33D1057626

Nassau Immediate Medical Care PLLC · Williston Park, NY
Expired · Sep 30, 2026
CLIA Number33D1057626
Laboratory TypePhysician Office
Certificate Effective DateJuly 24, 2023
Certificate Expiration DateSeptember 30, 2026
Laboratory DirectorSusan P. Welgrin
Laboratory Phone(516) 294-3535
Laboratory LocationNassau Immediate Medical Care PLLC465 Willis Avenue, Williston Park, NY 11596
CLIA data matches this NPI record on: Address Phone
This certificate is issued to a laboratory after an inspection that finds the laboratory to be in compliance with all applicable CLIA requirements.

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 Nassau Immed Med Care PLLC's NPI number?

The NPI number for Nassau Immed Med Care PLLC is 1255429254. It was assigned to this organization in the NPPES registry on October 11, 2006.

Where is Nassau Immed Med Care PLLC located?

Nassau Immed Med Care PLLC is located at 465 Willis Ave, Williston Park, NY 11596. The listed phone number is (516) 294-3535.

What is Nassau Immed Med Care PLLC's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Is Nassau Immed Med Care PLLC enrolled in Medicare?

Yes. Nassau Immed Med Care PLLC is registered in the Medicare PECOS enrollment system.

How many clinicians bill Medicare through Nassau Immed Med Care PLLC?

According to the CMS Revalidation Reassignment List (October 2026 release), 1 clinician (Internal Medicine) reassigns their Medicare billing to Nassau Immed Med Care PLLC. A reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for the clinician's services. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

When was this NPI record last updated?

The NPPES record for Nassau Immed Med Care PLLC was last updated on March 17, 2008. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 18 years 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.