Quick answers
- Which hospitals does Gregory Siaumau work at?
- Medicare's official clinician data lists Gregory Siaumau at 2 hospitals: Grossmont Hospital and UC San Diego Health Hillcrest - Hillcrest Medical Center. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Gregory Siaumau see patients?
- Medicare's clinician data lists 4 practice locations, including El Cajon, CA, San Diego, CA and Santee, CA. Call before your visit to confirm the address.
- What is Gregory Siaumau's specialty?
- Medicare lists Nurse Practitioner as the primary specialty.
- Does Gregory Siaumau accept Medicare assignment?
- Yes. Medicare's clinician data says Gregory Siaumau 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 Gregory Siaumau?
- (619) 431-4877, as listed in official Medicare / NPI Registry data.
- What is Gregory Siaumau's NPI number?
- 1609583392. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Gregory Siaumau works
Medicare's Facility Affiliation Data lists Gregory Siaumau at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Grossmont HospitalLa Mesa, CA · Acute Care Hospital · CCN 050026
- UC San Diego Health Hillcrest - Hillcrest Medical CenterSan Diego, CA · Acute Care Hospital · CCN 050025
Practice locations
Addresses where Gregory Siaumau is enrolled with Medicare (CMS data updated 2026-10-02).
- 215 W Madison AveEl Cajon, CA 92020 (619) 431‑4877
- 4537 College AveSan Diego, CA 92115 (619) 229‑1895
- 5538 University AveSan Diego, CA 92105 (619) 431‑4877
- 8770 Cuyamaca St, Suite 4Santee, CA 92071 (619) 596‑9890
Group practices
Medicare enrollment lists Gregory Siaumau as a member of this group (CMS data updated 2026-10-02).
- Yashwant Chaudhri MD a Prof Corp5 clinicians in the group
Specialties
- Nurse Practitionerprimary
Other nurse practitioners in El Cajon
Clinicians with the same Medicare primary specialty in El Cajon, CA — not a recommendation.
Clinician information
| Credential | NP |
|---|---|
| Graduation year | 2024 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1609583392 |
| 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