Quick answers
- Which hospitals does David R. Onsager work at?
- Medicare's official clinician data lists David R. Onsager at 3 hospitals: Northshore University Healthsystem - Evanston Hospital, The University of Chicago Medical Center and UChicago Medicine AdventHealth Hinsdale. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does David R. Onsager see patients?
- Medicare's clinician data lists 2 practice locations, including Evanston, IL and Chicago, IL. Call before your visit to confirm the address.
- What is David R. Onsager's specialty?
- Medicare lists Cardiac Surgery as the primary specialty, and also Thoracic Surgery.
- Does David R. Onsager accept Medicare assignment?
- Yes. Medicare's clinician data says David R. Onsager accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
- What is the phone number for David R. Onsager?
- (847) 570-1070, as listed in official Medicare / NPI Registry data.
- What is David R. Onsager's NPI number?
- 1396829156. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where David R. Onsager works
Medicare's Facility Affiliation Data lists David R. Onsager at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Northshore University Healthsystem - Evanston HospitalEvanston, IL · Acute Care Hospital · CCN 140010
- The University of Chicago Medical CenterChicago, IL · Acute Care Hospital · CCN 140088
- UChicago Medicine AdventHealth HinsdaleHinsdale, IL · Acute Care Hospital · CCN 140122
Practice locations
Addresses where David R. Onsager is enrolled with Medicare (CMS data updated 2026-10-02).
- 2650 Ridge Ave, Suite 1155Evanston, IL 60201 (847) 570‑1070
- 5841 S Maryland AveChicago, IL 60637 (773) 702‑1000
Group practices
Medicare enrollment lists David R. Onsager as a member of these groups (CMS data updated 2026-10-02).
- Endeavor Health Medical Group3,350 clinicians in the group
- University of Chicago1,712 clinicians in the group
- The University of Chicago Medical Center915 clinicians in the group
Specialties
- Cardiac Surgeryprimary
- Thoracic Surgeryalso
Other cardiac surgeons in Illinois
Clinicians with the same Medicare primary specialty in Illinois — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Rush Medical College Of Rush University |
| Graduation year | 1988 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1396829156 |
| 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 2026-10-02, retrieved 2026-10-29
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- 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