Quick answers
- Does Niamh M. Keegan accept Medicare assignment?
- Yes. Medicare's clinician data says Niamh M. Keegan 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 Niamh M. Keegan see?
- In 2024, CMS data shows 311 Original Medicare patients and 1,113 services for Niamh M. Keegan. This counts Original Medicare only and measures volume, not quality.
- What is Niamh M. Keegan's NPI number?
- 1811487127. 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 Niamh M. Keegan, 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 patients | 311 |
|---|---|
| Services billed to Medicare | 1,113 |
| Different services or procedures | 13 |
| Participating Medicare provider | Yes |
| Average age of these patients | 76 |
Most frequent services
- Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)542 services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)312 services
- Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more (99215)117 services
- New patient office or other outpatient visit with a high level of medical decision making, if using time, 60 minutes or more (99205)79 services
- Telephone medical discussion with physician, 5-10 minutes (99441)13 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).
- High blood pressure75%
- High cholesterol75%
- Cancer (breast, colorectal, lung, prostate, endometrial or leukemia/lymphoma)75%
- Arthritis41%
- Ischemic heart disease38%
- Chronic kidney disease31%
Hospitals where Niamh M. Keegan works
Medicare's Facility Affiliation Data lists Niamh M. Keegan 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.
- Sharon HospitalSharon, CT · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 070004
Practice locations
Addresses where Niamh M. Keegan is enrolled with Medicare (CMS data updated October 2, 2026).
- 1101 Hempstead TpkeUniondale, NY 11553 (212) 639‑2000
- 1275 York AveNew York, NY 10021 (212) 639‑2131
- 500 Westchester AveWest Harrison, NY 10604 (212) 639‑2000
Group practices
Medicare enrollment lists Niamh M. Keegan as a member of these groups (CMS data updated October 2, 2026).
- Memorial Solid Tumor Group234 clinicians in the group
- MSK Harrison132 clinicians in the group
- MSK Nassau98 clinicians in the group
Specialties
- Medical Oncologyprimary
- Internal Medicinealso
Other oncologists in Uniondale
Clinicians with the same Medicare primary specialty in Uniondale, NY — not a recommendation.
Other clinicians in Memorial Solid Tumor Group
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Graduation year | 2010 (16 years since medical school) |
|---|---|
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1811487127 |
| Corrections | Report 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
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians