Quick answers
- Which hospitals does Choon S. Koo work at?
- Medicare's official clinician data lists Choon S. Koo at 2 hospitals: Mountains Community Hospital and San Antonio Regional Hospital. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Choon S. Koo see patients?
- Medicare's clinician data lists 1 practice location in Upland, CA. Call before your visit to confirm the address.
- What is Choon S. Koo's specialty?
- Medicare lists Pathology as the primary specialty.
- Does Choon S. Koo accept Medicare assignment?
- Yes. Medicare's clinician data says Choon S. 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 Choon S. Koo's NPI number?
- 1265427595. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Choon S. Koo works
Medicare's Facility Affiliation Data lists Choon S. Koo at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Mountains Community HospitalLake Arrowhead, CA · Critical Access Hospital · CCN 051312
- San Antonio Regional HospitalUpland, CA · Acute Care Hospital · CCN 050099
Practice locations
Addresses where Choon S. Koo is enrolled with Medicare (CMS data updated 2026-10-02).
- 999 San Bernardino RdUpland, CA 91786
Group practices
Medicare enrollment lists Choon S. Koo as a member of this group (CMS data updated 2026-10-02).
- Excel Pathology4 clinicians in the group
Specialties
- Pathologyprimary
Other pathologists in California
Clinicians with the same Medicare primary specialty in California — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 1968 |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1265427595 |
| 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