DR. GREGORY CARTER WILLIAMSON MD
NPI 1144780040
Anesthesiology in Pittsburgh, PA

Q: What is Gregory Williamson's NPI number?

The NPI number for Gregory Williamson is 1144780040. It was assigned to this individual provider in the NPPES registry on March 25, 2019.

Q: What is Gregory Williamson's specialty?

The primary specialty registered for this NPI is Anesthesiology with taxonomy code 207L00000X.

Active since March 25, 2019PECOS EnrolledAccepts Medicare Assignment

4401 PENN AVE STE 5643, PITTSBURGH, PA 15224(412) 692-5261 Get Directions Write a Review

NPPES record last updated: April 8, 2025. Verified against the NPPES registry weekly; last sync: November 08, 2026.

Record update history: Apr 8, 2025, Jun 17, 2024 (2 updates tracked since 2024).

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About Dr. Gregory Carter Williamson Md NPPES

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

DR. GREGORY CARTER WILLIAMSON MD (NPI 1144780040) is an individual anesthesiology provider in Pittsburgh, Pennsylvania, licensed in Pennsylvania (MD484869) and active in the NPI registry since March 2019. He is enrolled in Medicare PECOS and is a graduate of Pennsylvania State University College Of Medicine (2019).

NPPES Registry Identity

NPI1144780040

Entity TypeIndividualMale

Primary Taxonomy207L00000X

Provider Legal NameDR. GREGORY CARTER WILLIAMSONCredential: MD

Location Address4401 PENN AVE STE 5643Pittsburgh, PA 15224-1334

Mailing Address4401 Penn AvePittsburgh, PA 15224-1334

Phone(412) 692-5261

Sole ProprietorNo

Medical School CMSPennsylvania State University College Of MedicineGraduated 2019

Enumeration DateMarch 25, 2019

Last NPPES UpdateApril 8, 20252 updates tracked since enumeration

NPPES CertifiedApril 8, 2025

✔ NPI 1144780040 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyAnesthesiologyAllopathic & Osteopathic Physicians

Taxonomy Code207L00000X

License✔ Licensed in PA · MD484869

Definition

An anesthesiologist is trained to provide pain relief and maintenance, or restoration, of a stable condition during and immediately following an operation or an obstetric or diagnostic procedure. The anesthesiologist assesses the risk of the patient undergoing surgery and optimizes the patient's condition prior to, during and after surgery. In addition to these management responsibilities, the anesthesiologist provides medical management and consultation in pain management and critical care medicine. Anesthesiologists diagnose and treat acute, long-standing and cancer pain problems; diagnose and treat patients with critical illnesses or severe injuries; direct resuscitation in the care of patients with cardiac or respiratory emergencies, including the need for artificial ventilation; and supervise post-anesthesia recovery.

Also ListedPediatricsTaxonomy 208000000X · License MD484869 (PA)

4401 PENN AVE STE 5643, Pittsburgh, PA 15224

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Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare and accepts Medicare assignment

Dr. Gregory Carter Williamson Md is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.

PECOS PAC ID9032444955

PECOS Enrollment IDI20251104004760

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.

Medicare Billing Reassignment

Medicare enrollment records show Gregory Williamson reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

University Of Pittsburgh Physicians

Same address

Pediatrics

4401 PENN AVE
Pittsburgh, PA 15224

Reassigned Medicare billing, Pennsylvania enrollment
7,114 clinicians in this Medicare group

NPI 1225096639 (412) 692-5325

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

Other Providers at the Same Location NPPES 2

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

ALEXANDER PRASLICK

Anesthesiology (Pediatric Anesthesiology)

4401 PENN AVE STE 5643, ONE CHILDREN'S HOSPITAL DRIVE
PITTSBURGH, PA 15224

Allegheny County (412) 692-5260

DANIEL GREGORY SPRINGER MD

Anesthesiology (Pediatric Anesthesiology)

4401 PENN AVE STE 5643
PITTSBURGH, PA 15224

Allegheny County (412) 692-7326

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 Gregory Williamson's NPI number?

The NPI number for Gregory Williamson is 1144780040. It was assigned to this individual provider in the NPPES registry on March 25, 2019.

Where is Gregory Williamson located?

Gregory Williamson practices at 4401 Penn Ave Ste 5643, Pittsburgh, PA 15224. The listed phone number is (412) 692-5261.

What is Gregory Williamson's specialty?

The primary specialty registered for this NPI is Anesthesiology with taxonomy code 207L00000X.

Is Gregory Williamson enrolled in Medicare?

Yes. Gregory Williamson is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.

Which organization bills Medicare for Gregory Williamson's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Gregory Williamson reassigns Medicare benefits to University Of Pittsburgh Physicians (Pittsburgh, PA). The 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 Gregory Williamson's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

When was this NPI record last updated?

The NPPES record for Gregory Williamson was last updated on April 8, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 19 months 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.