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Hematology/Oncology

Mary S. Donnelly, MD

Works at hospitals in Athol, MA · Gardner, MA · Worcester, MA · Massachusetts

Summary

Dr. Mary S. Donnelly, MD is a hematologist-oncologist at 242 Green St, Gardner, MA 01440. Phone: (978) 632-3420. Accepts Medicare assignment. In 2024, Mary S. Donnelly had 132 Original Medicare patients and 477 services. NPI 1942297528. Source: CMS National Downloadable File, updated October 2, 2026; CMS Facility Affiliation Data, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

From official Medicare data

This page shows what Medicare's official clinician data says about Mary S. Donnelly, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does Mary S. Donnelly accept Medicare assignment?
Yes. Medicare's clinician data says Mary S. Donnelly accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
How many Medicare patients does Mary S. Donnelly see?
In 2024, CMS data shows 132 Original Medicare patients and 477 services for Mary S. Donnelly. This counts Original Medicare only and measures volume, not quality.
What is Mary S. Donnelly's NPI number?
1942297528. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.

Medicare activity in 2024

Official CMS public-use data for Mary S. Donnelly, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.

Original Medicare patients132
Services billed to Medicare477
Different services or procedures5
Participating Medicare providerYes
Average age of these patients75

Most frequent services

  1. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)278 services
  2. Visit complexity inherent to evaluation and management associated with medical care services that serve as the continuing focal point for all needed health care services and/or with medical care services that are part of ongoing care related to a patient's (G2211)154 services
  3. Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more (99215)20 services
  4. New patient office or other outpatient visit with a high level of medical decision making, if using time, 60 minutes or more (99205)16 services

Chronic conditions among these patients

Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).

  • Cancer (breast, colorectal, lung, prostate, endometrial or leukemia/lymphoma)75%
  • High blood pressure72%
  • High cholesterol71%
  • Arthritis39%
  • Anxiety31%
  • Diabetes26%

Hospitals where Mary S. Donnelly works

Medicare's Facility Affiliation Data lists Mary S. Donnelly at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.

Practice locations

Addresses where Mary S. Donnelly is enrolled with Medicare (CMS data updated October 2, 2026).

Group practices

Medicare enrollment lists Mary S. Donnelly as a member of this group (CMS data updated October 2, 2026).

  • Henry Heywood Memorial Hospital115 clinicians in the group

Specialties

Find other Hematology/Oncology doctors in Massachusetts →

Other hematologist-oncologists in Massachusetts

Clinicians with the same Medicare primary specialty in Massachusetts — not a recommendation.

All hematologist-oncologists in Massachusetts →

Other clinicians in Henry Heywood Memorial Hospital

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

Clinician information

CredentialMD
Medical schoolClvlnd Clinic Lerner College Of Med Of Case Wstn Rsv University
Graduation year1974 (52 years since medical school)
Gender (as listed)Female
Medicare assignmentAccepts (Medicare-approved amount as full payment)
NPI (National Provider Identifier)1942297528
CorrectionsReport an error or suggest an update →

Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.

Sources

  1. Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
  2. Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
  3. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  4. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
  5. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  6. Medicare Care Compare — official Medicare tool to look up clinicians