William Chen
NPI 1366837890 · Gastroenterology Physician · San Diego, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Provider details
- NPI number
- 1366837890
- Entity type
- Individual
- Primary specialty
- Gastroenterology PhysicianAllopathic & Osteopathic Physicians
- Sex
- Male
- Sole proprietor
- No
- License
- A184576 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
11 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
2 documented practice locations
- Medicare service volume (vs. specialty peers)25% of score
767 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 High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 144 | $187 |
| Biopsy of Esophagus, Stomach, And/Or Upper Small Bowel Using a Flexible Endoscope43239 | 111 | $90 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 111 | $137 |
| Removal of Polyps Or Growths of Large Bowel Using an Endoscope With Mechanical Snare45385 | 63 | $250 |
| Biopsy of Large Bowel Using a Flexible Endoscope45380 | 62 | $106 |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 18 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Pantoprazole Sodium | 192 | 68 |
| Omeprazole | 179 | 68 |
| Sodium, Potassium,mag Sulfatesbrand: Sod Sulf-Potass Sulf-Mag Sulf | 123 | 120 |
| Linaclotidebrand: Linzess | 101 | 26 |
| Famotidine | 80 | 34 |
| Prednisone | 44 | — |
| Sod Picosulf/Mag Ox/Citric Acbrand: Clenpiq |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$1,622 across 78 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
Additional practice locations (1)
- 15611 Pomerado Rd Ste 500Poway, CA 92064-2438Phone: (858) 292-7527Fax: (858) 292-7804
Registry dates
- Enumerated
- 2015-04-01
- Last updated
- 2026-05-13
- Certified
- 2026-05-13
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.