Quick answers
- Does Guerin T. Williams accept Medicare assignment?
- Yes. Medicare's clinician data says Guerin T. 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 Guerin T. Williams see?
- In 2024, CMS data shows 342 Original Medicare patients and 1,576 services for Guerin T. Williams. This counts Original Medicare only and measures volume, not quality.
- What is Guerin T. Williams's NPI number?
- 1750564787. 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 Guerin T. 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 | 342 |
|---|---|
| Services billed to Medicare | 1,576 |
| Different services or procedures | 26 |
| Participating Medicare provider | Yes |
| Average age of these patients | 74 |
Most frequent services
- Ultrasound measurement of bladder capacity after voiding (51798)238 services
- Established patient office or other outpatient visit with straightforward medical decision making, if using time, 10 minutes or more (99212)76 services
- Diagnostic exam of bladder and urethra using an endoscope (52000)59 services
- New patient office or other outpatient visit with straightforward medical decision making, if using time, 15 minutes or more (99202)34 services
- Complex measurement of pressure of urine flow in bladder with voiding pressure studies (51728)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 pressure72%
- Arthritis42%
- Ischemic heart disease36%
- Diabetes28%
- Chronic kidney disease27%
Hospitals where Guerin T. Williams works
Medicare's Facility Affiliation Data lists Guerin T. 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 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 Guerin T. Williams is enrolled with Medicare (CMS data updated October 2, 2026). The first 5 of 6; the Medicare profile lists all.
- 1333 W Belmont AveChicago, IL 60657
- 4445 W Irving Park RdChicago, IL 60641
- 4732 N Lincoln AveChicago, IL 60625 (847) 475‑2273
- 4732 N Lincoln Ave, Suite 200Chicago, IL 60625 (312) 926‑6000
- 675 N Saint Clair StChicago, IL 60611
Group practices
Medicare enrollment lists Guerin T. Williams as a member of this group (CMS data updated October 2, 2026).
- Northwestern Medical Faculty Foundation4,503 clinicians in the group
Specialties
- Physician Assistantprimary
Other physician assistants in Chicago
Clinicians with the same Medicare primary specialty in Chicago, 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
| Graduation year | 2004 |
|---|---|
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1750564787 |
| 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