Quick answers
- Does Rebecca L. Williams accept Medicare assignment?
- Yes. Medicare's clinician data says Rebecca L. Williams 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 Rebecca L. Williams see?
- In 2024, CMS data shows 85 Original Medicare patients and 199 services for Rebecca L. Williams. This counts Original Medicare only and measures volume, not quality.
- What is Rebecca L. Williams's NPI number?
- 1538509294. 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 Rebecca L. Williams, 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 | 85 |
|---|---|
| Services billed to Medicare | 199 |
| Different services or procedures | 22 |
| Participating Medicare provider | Yes |
| Average age of these patients | 74 |
Most frequent services
- New patient office or other outpatient visit with a high level of medical decision making, if using time, 60 minutes or more (99205)70 services
- Fine needle aspiration biopsy using ultrasound guidance, first growth (10005)41 services
- Fine needle aspiration biopsy using ultrasound guidance, each additional growth (10006)14 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%
- High blood pressure68%
- Arthritis32%
- Osteoporosis27%
- Ischemic heart disease25%
- Diabetes24%
Hospitals where Rebecca L. Williams works
Medicare's Facility Affiliation Data lists Rebecca L. Williams 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.
- Northwestern Lake Forest HospitalLake Forest, IL · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 140130
- Northwestern Medicine Central Dupage HospitalWinfield, IL · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 140242
- Northwestern Memorial HospitalChicago, IL · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 140281
Practice locations
Addresses where Rebecca L. Williams is enrolled with Medicare (CMS data updated October 2, 2026). The first 5 of 7; the Medicare profile lists all.
Group practices
Medicare enrollment lists Rebecca L. Williams as a member of this group (CMS data updated October 2, 2026).
- Northwestern Medical Faculty Foundation4,503 clinicians in the group
Specialties
- Surgical Oncologyprimary
Other surgical oncologists in Evanston
Clinicians with the same Medicare primary specialty in Evanston, IL — not a recommendation.
Other clinicians in Northwestern Medical Faculty Foundation
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Medical school | Oregon Health Sciences University School Of Medicine |
|---|---|
| Graduation year | 2015 (11 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) | 1538509294 |
| 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