Warren Joseph A. San Diego, MD
NPI 1083036743ActiveIndividual· Internal Medicine· Fairfield, CA
Internal Medicine (MD) with Northbay Physicians Surgery Center, LLC, practicing in Fairfield, California. 331 Medicare patients in 2024, $83,517 paid; nearly all of their 443 Part D prescriptions were generic (91%). Lists Northbay Medical Center as a hospital affiliation.
Overview
| NPI | 1083036743 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Jan 15, 2014 |
| Last updated in NPPES | Jul 22, 2019 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine Primary | 207R00000X | A130099 | CA |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Nov 10, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 11, 2026 | No match | — |
| New York OMIG · Nov 11, 2026 | No match | — |
| Ohio Medicaid · Nov 11, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 11, 2026 | No match | — |
| Washington HCA · Nov 11, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Internal Medicine (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 331 |
|---|---|
| Services billed | 874 across 10 procedure codes |
| Paid by Medicare | $83,517 |
Part D prescriptions in 2024
| Prescriptions (claims) | 443 · 499 30-day fills |
|---|---|
| Patients | 147 |
| Total drug cost | $20,402 |
| Generic share | 91% of claims |
Education and affiliations
| Graduation year | 2011 |
|---|---|
| Medicare specialty | Internal Medicine |
Medical group
- Northbay Physicians Surgery Center, LLCFairfield, CA · 324 clinicians
Hospital affiliation
- Northbay Medical CenterFairfield, CA
Other facilities
- Bristol Hospice - East BayHospice · Pleasanton, CA
- Bristol Hospice - Sacramento, LLCHospice · Roseville, CA
- Continuum Care Hospice LLCHospice · Concord, CA
Industry payments (Open Payments)
None reported for 2025 or 2024.
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 65 internal medicine physicians in Fairfield · All internal medicine physicians in California