Quick answers
- Which hospitals does Ralph A. Koo work at?
- Medicare's official clinician data lists Ralph A. Koo at 2 hospitals: NorthBay Medical Center and San Joaquin General Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Ralph A. Koo see patients?
- Medicare's clinician data lists 3 practice locations, including Vacaville, CA, Fairfield, CA and French Camp, CA. Call before your visit to confirm the address.
- What is Ralph A. Koo's specialty?
- Medicare lists Emergency Medicine as the primary specialty.
- Does Ralph A. Koo accept Medicare assignment?
- Yes. Medicare's clinician data says Ralph A. Koo 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 Ralph A. Koo?
- (707) 624-7000, as listed in official Medicare / NPI Registry data.
- What is Ralph A. Koo's NPI number?
- 1205932050. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Ralph A. Koo works
Medicare's Facility Affiliation Data lists Ralph A. Koo at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- NorthBay Medical CenterFairfield, CA · Acute Care Hospital · CCN 050367
- San Joaquin General HospitalFrench Camp, CA · Acute Care Hospital · CCN 050167
Practice locations
Addresses where Ralph A. Koo is enrolled with Medicare (CMS data updated 2026-10-02).
- 1000 Nut Tree RdVacaville, CA 95687 (707) 624‑7000
- 1200 B Gale Wilson BlvdFairfield, CA 94533 (707) 429‑3600
- 500 W Hospital RdFrench Camp, CA 95231 (209) 468‑6000
Group practices
Medicare enrollment lists Ralph A. Koo as a member of these groups (CMS data updated 2026-10-02).
- Cep America - California1,292 clinicians in the group
- NorthBay Physicians Surgery Center, LLC324 clinicians in the group
Specialties
- Emergency Medicineprimary
Other emergency medicine doctors in Vacaville
Clinicians with the same Medicare primary specialty in Vacaville, CA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of South Carolina School Of Medicine |
| Graduation year | 1993 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1205932050 |
| 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