John Leong, DO
NPI 1851896773 · Student in an Organized Health Care Education/Training Program · Fontana, CA
Enrolled with Medicare as Practitioner - Geriatric Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
John Leong, DO is a Student in an Organized Health Care Education/Training Program provider in Fontana, CA (NPI 1851896773).
Provider details
- NPI number
- 1851896773
- Entity type
- Individual
- Primary specialty
- Student in an Organized Health Care Education/Training ProgramStudent, Health Care
- Credential
- DO
- Sex
- Male
- Sole proprietor
- No
Specialties & taxonomies
Student, Health Care
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
8 yrs in NPPES registry
- Profile completeness38% of score
83% of core fields populated
- Practice footprint23% of score
1 documented practice location
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 6 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Donepezil Hcl | 109 | 43 |
| Memantine Hcl | 77 | 35 |
| Buspirone Hcl | 69 | 37 |
| Quetiapine Fumarate | 69 | 30 |
| Trazodone Hcl | 60 | 37 |
| Sertraline Hcl | 51 | 19 |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means , never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Practice location
Mailing address
Registry dates
- Enumerated
- 2018-03-25
- Last updated
- 2022-11-21
Frequently asked questions
- What is John Leong's NPI number?
- John Leong's National Provider Identifier (NPI) is 1851896773, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is John Leong's specialty?
- John Leong is listed in the NPPES registry with a primary specialty of Student in an Organized Health Care Education/Training Program (Student, Health Care).
- Where is John Leong located?
- John Leong's practice location on file with NPPES is 9961 Sierra Ave, Fontana, CA 92335-6720.
- What is John Leong's phone number?
- The practice phone number listed in the NPPES registry for John Leong is (833) 574-2273.
- Does John Leong accept Medicare?
- John Leong is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is John Leong's NPI active?
- Yes — John Leong's NPI (1851896773) is active in the NPPES registry as of the last update on 2022-11-21.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.