Gemma Jean Jamena, MD
NPI 1962761924 · Family Medicine Physician · Fremont, CA
Enrolled with Medicare as Practitioner - Family Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Gemma Jean Jamena, MD is a Family Medicine Physician provider in Fremont, CA (NPI 1962761924).
Provider details
- NPI number
- 1962761924
- Entity type
- Individual
- Primary specialty
- Family Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- Yes
- License
- A127649 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure33% of score
14 yrs in NPPES registry
- Profile completeness33% of score
100% of core fields populated
- Practice footprint20% of score
1 documented practice location
- Open Payments transparency13% of score
Has Open Payments disclosures (2024)
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 · 97 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Losartan Potassium | 207 | 68 |
| Atorvastatin Calcium | 196 | 69 |
| Metformin Hcl | 154 | 44 |
| Levothyroxine Sodium | 148 | 43 |
| Amlodipine Besylate | 111 | 46 |
| Lisinopril | 109 | 29 |
| Albuterol Sulfate |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$41 across 2 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2012-05-11
- Last updated
- 2021-10-15
- Certified
- 2021-10-15
Frequently asked questions
- What is Gemma Jean Jamena's NPI number?
- Gemma Jean Jamena's National Provider Identifier (NPI) is 1962761924, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Gemma Jean Jamena's specialty?
- Gemma Jean Jamena is listed in the NPPES registry with a primary specialty of Family Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Gemma Jean Jamena located?
- Gemma Jean Jamena's practice location on file with NPPES is 39500 Liberty St, Fremont, CA 94538-2211.
- What is Gemma Jean Jamena's phone number?
- The practice phone number listed in the NPPES registry for Gemma Jean Jamena is (510) 770-8040.
- Does Gemma Jean Jamena accept Medicare?
- Gemma Jean Jamena is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Gemma Jean Jamena's NPI active?
- Yes — Gemma Jean Jamena's NPI (1962761924) is active in the NPPES registry as of the last update on 2021-10-15.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.