Quick answers
- Does Ellen L. Ziaja accept Medicare assignment?
- Yes. Medicare's clinician data says Ellen L. Ziaja 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 Ellen L. Ziaja see?
- In 2024, CMS data shows 198 Original Medicare patients and 1,554 services for Ellen L. Ziaja. This counts Original Medicare only and measures volume, not quality.
- What is Ellen L. Ziaja's NPI number?
- 1104868181. 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 Ellen L. Ziaja, 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 | 198 |
|---|---|
| Services billed to Medicare | 1,554 |
| Different services or procedures | 29 |
| Participating Medicare provider | Yes |
| Average age of these patients | 74 |
Most frequent services
- Ct guidance for insertion of radiation therapy fields (77014)695 services
- Radiation treatment management, 5 treatment sessions (77427)216 services
- Calculation of radiation therapy dose (77300)145 services
- Design and construction of complex radiation treatment device (77334)67 services
- Intra-fraction localization and tracking of target or patient motion during delivery of radiation therapy (eg,3d positional tracking, gating, 3d surface tracking), each fraction of treatment (G6017)66 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 cholesterol75%
- Cancer (breast, colorectal, lung, prostate, endometrial or leukemia/lymphoma)75%
- High blood pressure72%
- Arthritis45%
- Ischemic heart disease39%
- Chronic kidney disease33%
Hospitals where Ellen L. Ziaja works
Medicare's Facility Affiliation Data lists Ellen L. Ziaja 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.
- Aurora BayCare Medical CenterGreen Bay, WI · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 520193
- Aurora Medical Center - SummitSummit, WI · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 520206
- Aurora St Lukes Medical CenterMilwaukee, WI · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 520138
- West Allis Memorial HospitalWest Allis, WI · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 520139
Practice locations
Addresses where Ellen L. Ziaja is enrolled with Medicare (CMS data updated October 2, 2026). The first 5 of 7; the Medicare profile lists all.
- 1222 N 23rd StSheboygan, WI 53081 (920) 457‑6800
- 2845 Greenbrier RdGreen Bay, WI 54311 (920) 288‑4160
- 2900 W Oklahoma AveMilwaukee, WI 53215 (414) 649‑6420
- 36500 Aurora DrSummit, WI 53066 (262) 434‑1800
- 6811 118th AveKenosha, WI 53142 (262) 857‑5700
Group practices
Medicare enrollment lists Ellen L. Ziaja as a member of this group (CMS data updated October 2, 2026).
- Radiation Oncology Associates Ltd24 clinicians in the group
Specialties
- Radiation Oncologyprimary
Other radiation oncologists in Sheboygan
Clinicians with the same Medicare primary specialty in Sheboygan, WI — not a recommendation.
Other clinicians in Radiation Oncology Associates Ltd
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Wayne State University School Of Medicine |
| Graduation year | 1993 (33 years since medical school) |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1104868181 |
| 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