Quick answers
- Does Margaret S. O'Brien accept Medicare assignment?
- Yes. Medicare's clinician data says Margaret S. O'Brien 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.
- What is Margaret S. O'Brien's NPI number?
- 1134700495. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Margaret S. O'Brien works
Medicare's Facility Affiliation Data lists Margaret S. O'Brien 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.
- Ingalls Memorial HospitalHarvey, IL · Acute Care Hospital · Medicare rating: 2 of 5 stars · Emergency services: listed by Medicare · CCN 140191
- The University of Chicago Medical CenterChicago, IL · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 140088
Practice locations
Addresses where Margaret S. O'Brien is enrolled with Medicare (CMS data updated October 2, 2026).
- 5841 S Maryland AveChicago, IL 60637 (773) 702‑1000
Group practices
Medicare enrollment lists Margaret S. O'Brien as a member of these groups (CMS data updated October 2, 2026).
- University of Chicago1,712 clinicians in the group
- The University of Chicago Medical Center915 clinicians in the group
Specialties
- Psychiatryprimary
Other psychiatrists in Chicago
Clinicians with the same Medicare primary specialty in Chicago, IL — not a recommendation.
Other clinicians in University of Chicago
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Texas Medical School At Houston |
| Graduation year | 2021 (5 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) | 1134700495 |
| 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
- 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