Tammy Chen, MD
NPI 1093887721 · Family Medicine Physician · Oakland, CA
Enrolled with Medicare as Practitioner - Family Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Tammy Chen, MD is a Family Medicine Physician provider in Oakland, CA (NPI 1093887721).
Provider details
- NPI number
- 1093887721
- Entity type
- Individual
- Primary specialty
- Family Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- A90848 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
19 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
61 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. 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 does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Routine Electrocardiogram (ecg) Using at Least 12 Leads With Interpretation and Report93000 | 61 | $18 |
Typical Medicare-allowed amounts for these services range $18–$18 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 39 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Amlodipine Besylate | 117 | 54 |
| Famotidine | 109 | 65 |
| Atorvastatin Calcium | 109 | 49 |
| Baclofen | 97 | 62 |
| Albuterol Sulfatebrand: Albuterol Sulfate Hfa | 86 | 39 |
| Losartan Potassium | 78 | 36 |
| Gabapentin | 62 |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-11-15
- Last updated
- 2007-07-08
Frequently asked questions
- What is Tammy Chen's NPI number?
- Tammy Chen's National Provider Identifier (NPI) is 1093887721, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Tammy Chen's specialty?
- Tammy Chen is listed in the NPPES registry with a primary specialty of Family Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Tammy Chen located?
- Tammy Chen's practice location on file with NPPES is 818 Webster St, Oakland, CA 94607-4220.
- What is Tammy Chen's phone number?
- The practice phone number listed in the NPPES registry for Tammy Chen is (510) 986-6830.
- Does Tammy Chen accept Medicare?
- Tammy Chen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Tammy Chen's NPI active?
- Yes — Tammy Chen's NPI (1093887721) is active in the NPPES registry as of the last update on 2007-07-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.