Medical emergency?Emergency? Call 911. Nearest emergency roomsNearest ERs

Internal Medicine

Joel A. Wilsnack, MD

Works at hospitals in Lake Forest, IL · Winfield, IL · Chicago, IL … · Illinois

Summary

Dr. Joel A. Wilsnack, MD is an internal medicine doctor at 1333 W Belmont Ave, Chicago, IL 60657. Phone: (312) 926-6146. Accepts Medicare assignment. In 2024, Joel A. Wilsnack had 213 Original Medicare patients and 699 services. NPI 1427083062. Source: CMS National Downloadable File, updated October 2, 2026; CMS Facility Affiliation Data, updated October 2, 2026; CMS Medicare Physician & Other Practitioners, data year 2024.

From official Medicare data

This page shows what Medicare's official clinician data says about Joel A. Wilsnack, joined by NPI number (data updated October 2, 2026). It is not a recommendation or a rating. Call the office or hospital to confirm before you go.

In a medical emergency, call 911.

Quick answers

Does Joel A. Wilsnack accept Medicare assignment?
Yes. Medicare's clinician data says Joel A. Wilsnack 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 Joel A. Wilsnack see?
In 2024, CMS data shows 213 Original Medicare patients and 699 services for Joel A. Wilsnack. This counts Original Medicare only and measures volume, not quality.
What is Joel A. Wilsnack's NPI number?
1427083062. 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 Joel A. Wilsnack, 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 patients213
Services billed to Medicare699
Different services or procedures20
Participating Medicare providerYes
Average age of these patients74

Most frequent services

  1. Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)216 services
  2. Insertion of needle into vein for collection of blood sample (36415)156 services
  3. Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more (99215)140 services
  4. Influenza vaccine split virus, preservative free (90662)34 services
  5. Administration of influenza virus vaccine (G0008)34 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 pressure62%
  • Arthritis34%
  • Ischemic heart disease21%
  • Osteoporosis19%
  • Cancer (breast, colorectal, lung, prostate, endometrial or leukemia/lymphoma)19%

Hospitals where Joel A. Wilsnack works

Medicare's Facility Affiliation Data lists Joel A. Wilsnack 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.

Practice locations

Addresses where Joel A. Wilsnack is enrolled with Medicare (CMS data updated October 2, 2026). The first 5 of 8; the Medicare profile lists all.

Group practices

Medicare enrollment lists Joel A. Wilsnack as a member of this group (CMS data updated October 2, 2026).

  • Northwestern Medical Faculty Foundation4,503 clinicians in the group

Specialties

Find other Internal Medicine doctors in Illinois →

Other internal medicine doctors in Chicago

Clinicians with the same Medicare primary specialty in Chicago, IL — not a recommendation.

All internal medicine doctors in Chicago →

Other clinicians in Northwestern Medical Faculty Foundation

Medicare enrollment lists these clinicians in the same group practice — not a recommendation.

Clinician information

CredentialMD
Medical schoolNorthwestern University Feinberg Medical School
Graduation year1995 (31 years since medical school)
Gender (as listed)Male
Medicare assignmentAccepts (Medicare-approved amount as full payment)
TelehealthOffers telehealth services
NPI (National Provider Identifier)1427083062
CorrectionsReport 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

  1. Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
  2. Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
  3. National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
  4. Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
  5. NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
  6. Medicare Care Compare — official Medicare tool to look up clinicians