Fiona Chai-Tom, DO
Internal Medicine Physician · Riverside, CA
Fiona Chai-Tom, DO is an internal medicine physician with a practice address in Riverside, California, and NPI 1174104848, issued on Apr 15, 2021. Check the license (California 20A20694, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Fiona Chai-Tom
- Credential
- DO
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 20A20694 CA
Self-reported in NPPES; status is on the state search - Practice location
- 10800 Magnolia Ave, Riverside, CA 92505
- Phone
- (833) 574-2273
- Enumerated
- Apr 15, 2021
- Record last updated
- Jul 28, 2024
- Medicare enrollment
- Enrolled (PECOS I20241209001930); accepts Medicare assignment
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 17,696 in California → Look up another NPI →
Also registered at 10800 Magnolia Ave
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Fiona Chai-Tom in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A20694Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
94% fewer Medicare Part D claims than the average internal medicine physician in 2024
176 Medicare Part D claims for 64 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D.
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
Bills Medicare through one group practice
- Southern California Permanente Medical GroupRiverside, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Fiona Chai-Tom among 17,696 internal medicine physician records in California
Fiona Chai-Tom, DO is one of 17,696 internal medicine physician records with a practice address in California. 79% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2021, is newer than 92% of them.
- NPI issued2021 · 92% of these records are older, 5% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated2021 · median 2004 among the 11,065 with a school on file
- Record last updated2024 · 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 207R00000X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
187 internal medicine physician records list a practice address in Riverside
They are 187 of the 13,893 NPPES records with a practice address in Riverside, and 17,696 internal medicine physician records in California.
All 17,696 in California → Every provider in Riverside → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Susan Diethelm, MDRiverside, CA 925051023185857
- Kathleen Fanning, MDRiverside, CA 925051427125335
- Thanh Hoang, MDRiverside, CA 925051174690994
- Ricardo Lim, MDRiverside, CA 925051336216159
- Iwan Ong, MDRiverside, CA 925051265416739
- Humera Rana, M.D.Riverside, CA 925051801982632
- Terence Shum, MDRiverside, CA 925051124195946
- Harneet Singh, MDRiverside, CA 925051114094943
Common questions
What is Fiona Chai-Tom, DO's NPI number?
Fiona Chai-Tom, DO's National Provider Identifier (NPI) is 1174104848, issued on Apr 15, 2021. An NPI identifies a provider in billing; it is not a license.
Where is Fiona Chai-Tom, DO located?
The NPPES record lists a practice address at 10800 Magnolia Ave, Riverside, CA, 92505. Phone: (833) 574-2273. Providers update this record themselves, so call before visiting.
How can I verify Fiona Chai-Tom, DO's license?
NPPES lists California license number 20A20694, 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.
How much does Fiona Chai-Tom, DO prescribe under Medicare Part D?
In 2024, Fiona Chai-Tom, DO had 176 Medicare Part D claims for 64 beneficiaries; the average among internal medicine physician prescribers was 3,176. Part D covers Medicare prescriptions only.
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.