Quick answers
- Where does John J. Tsay see patients?
- Medicare's clinician data lists 2 practice locations, including Brookline, MA and Boston, MA. Call before your visit to confirm the address.
- What is John J. Tsay's specialty?
- Medicare lists Internal Medicine as the primary specialty.
- Does John J. Tsay accept Medicare assignment?
- Yes. Medicare's clinician data says John J. Tsay 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 John J. Tsay?
- (617) 363-8010, as listed in official Medicare / NPI Registry data.
- What is John J. Tsay's NPI number?
- 1164632691. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Practice locations
Addresses where John J. Tsay is enrolled with Medicare (CMS data updated 2026-10-02).
- 100 Centre StBrookline, MA 02446 (617) 363‑8010
- 133 Brookline AveBoston, MA 02215 (617) 421‑1000
Group practices
Medicare enrollment lists John J. Tsay as a member of these groups (CMS data updated 2026-10-02).
- Atrius Health Inc1,222 clinicians in the group
- Hebrew Rehabilitation Center49 clinicians in the group
Specialties
- Internal Medicineprimary
Other internal medicine doctors in Brookline
Clinicians with the same Medicare primary specialty in Brookline, MA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 2005 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1164632691 |
| 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
- 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