Quick answers
- Which hospitals does Margaret Callahan work at?
- Medicare's official clinician data lists Margaret Callahan at 1 hospital: John Dempsey Hospital of the University of Connect…. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Margaret Callahan see patients?
- Medicare's clinician data lists 1 practice location in Farmington, CT. Call before your visit to confirm the address.
- What is Margaret Callahan's specialty?
- Medicare lists Hematology/Oncology as the primary specialty.
- Does Margaret Callahan accept Medicare assignment?
- Yes. Medicare's clinician data says Margaret Callahan 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 Margaret Callahan?
- (860) 679-3692, as listed in official Medicare / NPI Registry data.
- What is Margaret Callahan's NPI number?
- 1508098534. 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 Callahan works
Medicare's Facility Affiliation Data lists Margaret Callahan at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- John Dempsey Hospital of the University of Connect…Farmington, CT · Acute Care Hospital · CCN 070036
Practice locations
Addresses where Margaret Callahan is enrolled with Medicare (CMS data updated 2026-10-02).
- 263 Farmington AveFarmington, CT 06030 (860) 679‑3692
Group practices
Medicare enrollment lists Margaret Callahan as a member of this group (CMS data updated 2026-10-02).
- University of Connecticut Health Center639 clinicians in the group
Specialties
- Hematology/Oncologyprimary
Other hematologist-oncologists in Farmington
Clinicians with the same Medicare primary specialty in Farmington, CT — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 2007 |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1508098534 |
| 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