Quick answers
- Does Stefanie Koelewyn accept Medicare assignment?
- Yes. Medicare's clinician data says Stefanie Koelewyn 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 Stefanie Koelewyn see?
- In 2024, CMS data shows 156 Original Medicare patients and 299 services for Stefanie Koelewyn. This counts Original Medicare only and measures volume, not quality.
- What is Stefanie Koelewyn's NPI number?
- 1811617897. 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 Stefanie Koelewyn, 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 | 156 |
|---|---|
| Services billed to Medicare | 299 |
| Different services or procedures | 38 |
| Participating Medicare provider | Yes |
| Average age of these patients | 73 |
Most frequent services
- New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)71 services
- Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)26 services
- New patient office or other outpatient visit with low level of medical decision making, if using time, 30 minutes or more (99203)25 services
- Emergency department visit with high level of medical decision making (99285)25 services
- Automated urinalysis test (81003)21 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 pressure68%
- High cholesterol64%
- Arthritis35%
- Anxiety27%
- Diabetes26%
- Depression24%
Hospitals where Stefanie Koelewyn works
Medicare's Facility Affiliation Data lists Stefanie Koelewyn 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.
- Brigham and Women's HospitalBoston, MA · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 220110
- Newton-Wellesley HospitalNewton, MA · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 220101
Practice locations
Addresses where Stefanie Koelewyn is enrolled with Medicare (CMS data updated October 2, 2026).
- 173 Worcester StWellesley, MA 02481 (671) 831‑7000
- 2014 Washington StNewton, MA 02462 (617) 243‑6000
Group practices
Medicare enrollment lists Stefanie Koelewyn as a member of this group (CMS data updated October 2, 2026).
- Mass General Brigham Medical Group Suburban Massachusetts Inc602 clinicians in the group
Specialties
- Physician Assistantprimary
Other physician assistants in Wellesley
Clinicians with the same Medicare primary specialty in Wellesley, MA — not a recommendation.
Other clinicians in Mass General Brigham Medical Group Suburban Massachusetts Inc
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Graduation year | 2022 |
|---|---|
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1811617897 |
| 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