Choon Sil Koo, M.D.
Anatomic Pathology & Clinical Pathology Physician · Upland, CA
Choon Sil Koo, M.D. is an anatomic pathology & clinical pathology physician with a practice address in Upland, California, and NPI 1265427595, issued on Sep 13, 2005. Check the license (California A31561, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Choon Sil Koo
- Credential
- M.D.
- Primary taxonomy
- Anatomic Pathology & Clinical Pathology Physician 207ZP0102X
- License number
- A31561 CA
Self-reported in NPPES; status is on the state search - Practice location
- 999 San Bernardino RD, Upland, CA 91786
- Phone
- (909) 985-2811
- Enumerated
- Sep 13, 2005
- Record last updated
- Jul 8, 2007 (not updated in 19 years: call before relying on the address or phone)
- Fax
- (909) 920-3827
- Medicaid ID
- 00A315610 CA
- Medicare enrollment
- Enrolled (PECOS I20090814000611); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest anatomic pathology & clinical pathology physician records → All 1,554 in California → Look up another NPI →
Also registered at 999 San Bernardino RD
A shared address usually means a shared clinic or building; it does not show who employs whom.
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- Ahmed Al-WaisiInternal Medicine Physician1871115709
- Donald Alpiner, DOSurgery Physician1811086952
- Alexander ArzooStudent in an Organized Health Care Education/Training Program1891635629
- Liezl Avila, D.O.Emergency Medicine Physician1487064515
Verify Choon Sil Koo in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license A31561Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
Bills Medicare through one group practice
- Excel PathologyUpland, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Choon Sil Koo among 1,554 anatomic pathology & clinical pathology physician records in California
Choon Sil Koo, M.D. is one of 1,554 anatomic pathology & clinical pathology physician records with a practice address in California. 65% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2005, is newer than 0% of them.
- NPI issued2005 · 0% of these records are older, 93% newer
- In a Medicare fileYes · 65% of these records are
- In the CMS Doctors and Clinicians fileYes · 57% of these records are
- Graduated1968 · median 2003 among the 891 with a school on file
- Record last updated2007 · 61% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207ZP0102X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Anatomic Pathology & Clinical Pathology Physician providers in California
There are 1,554 anatomic pathology & clinical pathology physician records in California.
All 1,554 in California → Every provider in Upland → Anatomic Pathology & Clinical Pathology Physician nationwide →
The 8 anatomic pathology & clinical pathology physician records with the nearest ZIP codes
- Howard Charman, M.D.Upland, CA 917861881689339
- Dulce Decastro, MDUpland, CA 917861508851064
- Armine Baltayan, MDSan Gabriel, CA 917761558568428
- Xiangdong Bu, MDSan Gabriel, CA 917761336108919
- Hong Li, MDSan Gabriel, CA 917761982664892
- Shirley Tan, MDSan Gabriel, CA 917761407816325
- Muh-Yau Tang, MDSan Gabriel, CA 917761831159755
- Sunita Vempati, MDSan Gabriel, CA 917761710946363
Common questions
What is Choon Sil Koo, M.D.'s NPI number?
Choon Sil Koo, M.D.'s National Provider Identifier (NPI) is 1265427595, issued on Sep 13, 2005. An NPI identifies a provider in billing; it is not a license.
Where is Choon Sil Koo, M.D. located?
The NPPES record lists a practice address at 999 San Bernardino RD, Upland, CA, 91786. Phone: (909) 985-2811. Providers update this record themselves, so call before visiting.
How can I verify Choon Sil Koo, M.D.'s license?
NPPES lists California license number A31561, as entered by the provider. Search the Medical Board of California at https://www.mbc.ca.gov/License-Verification/default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.