William Chen, MD
NPI 1851498372 · Internal Medicine Physician · San Pablo, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
William Chen, MD is a Internal Medicine Physician provider in San Pablo, CA (NPI 1851498372).
Provider details
- NPI number
- 1851498372
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- A070200 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
19 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
2,913 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
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 .
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) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 1,449 | $107 |
| Annual Alcohol Misuse Screening, 5 to 15 MinutesG0442 | 325 | $24 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 282 | $157 |
| Telephone Medical Discussion With Physician, 11-20 Minutes99442 | 268 | $74 |
| Administration of Influenza Virus VaccineG0008 | 189 | $39 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 155 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 212 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 946 | 286 |
| Amlodipine Besylate | 761 | 204 |
| Hydrocodone/Acetaminophenbrand: Hydrocodone-Acetaminophen | 730 | 103 |
| Metformin Hcl | 551 | 169 |
| Metoprolol Succinate | 417 | 124 |
| Losartan Potassium | 404 | 109 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$726 across 39 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
- 2006-09-19
- Last updated
- 2009-11-05
Frequently asked questions
- What is William Chen's NPI number?
- William Chen's National Provider Identifier (NPI) is 1851498372, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is William Chen's specialty?
- William Chen is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is William Chen located?
- William Chen's practice location on file with NPPES is 2089 Vale Rd, San Pablo, CA 94806.
- What is William Chen's phone number?
- The practice phone number listed in the NPPES registry for William Chen is (510) 235-9247.
- Does William Chen accept Medicare?
- William Chen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is William Chen's NPI active?
- Yes — William Chen's NPI (1851498372) is active in the NPPES registry as of the last update on 2009-11-05.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.