Quick answers
- Does Rebecca Leong accept Medicare assignment?
- Yes. Medicare's clinician data says Rebecca Leong 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 Rebecca Leong see?
- In 2024, CMS data shows 1,223 Original Medicare patients and 1,343 services for Rebecca Leong. This counts Original Medicare only and measures volume, not quality.
- What is Rebecca Leong's NPI number?
- 1922089952. 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 Rebecca Leong, 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 patients | 1,223 |
|---|---|
| Services billed to Medicare | 1,343 |
| Different services or procedures | 7 |
| Participating Medicare provider | Yes |
| Average age of these patients | 76 |
Most frequent services
- Anesthesia for lens surgery (00142)1,172 services
- Anesthesia for other procedure on eye (00140)87 services
- Anesthesia for retinal surgery (00145)49 services
- Anesthesia for procedure on eye for corneal transplant (00144)17 services
- Anesthesia for procedure on eyelid (00103)13 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 cholesterol73%
- High blood pressure66%
- Arthritis42%
- Anxiety22%
- Osteoporosis22%
- Ischemic heart disease21%
Practice locations
Addresses where Rebecca Leong is enrolled with Medicare (CMS data updated October 2, 2026).
- 1440 Main StWaltham, MA 02451 (781) 891‑9300
- 50 Staniford St, Lbby LevelBoston, MA 02114 (617) 723‑2015
Group practices
Medicare enrollment lists Rebecca Leong as a member of these groups (CMS data updated October 2, 2026).
- JJM Medical Services PC35 clinicians in the group
- Anesthesia Consultants of Massachusetts LLC9 clinicians in the group
Specialties
- Anesthesiologyprimary
Other anesthesiologists in Waltham
Clinicians with the same Medicare primary specialty in Waltham, MA — not a recommendation.
Other clinicians in JJM Medical Services PC
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Medical school | Harvard Medical School |
|---|---|
| Graduation year | 1988 (38 years since medical school) |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1922089952 |
| 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 October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- 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