PETER MARK GRZESIK DO
NPI 1518378231
Anesthesiology in Worcester, MA
About Peter Mark Grzesik Do NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
PETER MARK GRZESIK DO (NPI 1518378231) is an individual anesthesiology provider in Worcester, Massachusetts, licensed in Massachusetts (287786) and active in the NPI registry since May 2014. He is enrolled in Medicare PECOS, is affiliated with Umass Memorial Medical Center/university Campus, and maintains 2 additional practice locations.
NPPES Registry Identity
Specialties & Licenses
Secondary Practice Locations 2
Other Identifiers 1
Accepted Insurance
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
Peter Mark Grzesik Do 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.
Medicare Billing Reassignment
Medicare enrollment records show Peter Grzesik reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.
Worcester, MA 01655
- Reassigned Medicare billing, Massachusetts enrollment
- 2,902 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Areas of Expertise CMS Part B claims 11
Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.
Hospital Affiliations CMS Care Compare
Hospitals where this provider delivers care, identified from recent Medicare claims and place-of-service records.
Umass Memorial Medical Center/University Campus
Acute Care Hospitals · Worcester, MAMedicare Quality Performance CMS QPP · MIPS
Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.
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.
WORCESTER, MA 01655
WORCESTER, MA 01655
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 Peter Grzesik's NPI number?
The NPI number for Peter Grzesik is 1518378231. It was assigned to this individual provider in the NPPES registry on May 15, 2014.
Where is Peter Grzesik located?
Peter Grzesik practices at 55 Lake Ave N, Worcester, MA 01655. The listed phone number is (508) 334-3271.
What is Peter Grzesik's specialty?
The primary specialty registered for this NPI is Anesthesiology with taxonomy code 207L00000X.
Is Peter Grzesik enrolled in Medicare?
Yes. Peter Grzesik 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 Peter Grzesik's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Peter Grzesik reassigns Medicare benefits to Umass Memorial Medical Group Inc (Worcester, MA). 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 Peter Grzesik's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.
What insurance does Peter Grzesik accept?
Health plans from Taro Health list Peter Grzesik as in-network in at least one marketplace plan. Coverage varies by plan and year; verify with the insurer or the provider before a visit.
Is Peter Grzesik affiliated with any hospitals?
According to CMS data, Peter Grzesik is affiliated with Umass Memorial Medical Center/University Campus.
When was this NPI record last updated?
The NPPES record for Peter Grzesik was last updated on July 29, 2021. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 5 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.
# Peter Mark Grzesik, DO · NPI 1518378231
Anesthesiology physician in Worcester, Massachusetts. Individual provider, active in the CMS NPPES registry since May 15, 2014.
## Identity
- **NPI:** 1518378231 (Entity type: Individual)
- **Enumerated:** May 15, 2014
- **Primary specialty:** Anesthesiology · taxonomy 207L00000X
- **State license:** 287786 (Massachusetts)
- **Sole proprietor:** No
## Practice location
- **Address:** 55 LAKE AVE N, Worcester, MA 01655-0002
- **Phone:** (508) 334-3271 · **Fax:** (508) 856-5911
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** Umass Memorial Medical Group Inc (NPI 1760445373, Worcester, MA), under Medicare reassignment (form CMS-855R) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** New York College Of Osteo Medicine Of New York Institute Of Technology, class of 2014
## Record status
- **NPPES last updated:** July 29, 2021
- **Other identifiers:** Medicaid 110126355A (MA)
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Source: [NPI Profile](https://npiprofile.com/npi/1518378231) · Data from the CMS NPPES public registry.