Quick answers
- Which hospitals does Greta Perez work at?
- Medicare's official clinician data lists Greta Perez at 1 hospital: Contra Costa Regional Medical Center. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Greta Perez see patients?
- Medicare's clinician data lists 2 practice locations, including Walnut Creek, CA and Concord, CA. Call before your visit to confirm the address.
- What is Greta Perez's specialty?
- Medicare lists Family Practice as the primary specialty.
- Does Greta Perez accept Medicare assignment?
- Yes. Medicare's clinician data says Greta Perez accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of 2026-10-02. Ask the office to confirm before your visit.
- What is the phone number for Greta Perez?
- (925) 296-9000, as listed in official Medicare / NPI Registry data.
- What is Greta Perez's NPI number?
- 1306988423. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Greta Perez works
Medicare's Facility Affiliation Data lists Greta Perez at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Contra Costa Regional Medical CenterMartinez, CA · Acute Care Hospital · CCN 050276
Practice locations
Addresses where Greta Perez is enrolled with Medicare (CMS data updated 2026-10-02).
- 1450 Treat Blvd, Suite 160Walnut Creek, CA 94597 (925) 296‑9000
- 2700 Grant St, Suite 110Concord, CA 94520 (925) 674‑2500
Group practices
Medicare enrollment lists Greta Perez as a member of this group (CMS data updated 2026-10-02).
- John Muir Physician Network494 clinicians in the group
Specialties
- Family Practiceprimary
Other family doctors in Walnut Creek
Clinicians with the same Medicare primary specialty in Walnut Creek, CA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 1994 |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1306988423 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated 2026-10-02, retrieved 2026-10-29
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians