Iwan Sing-Djwan Ong, MD
Internal Medicine Physician · Riverside, CA
Iwan Sing-Djwan Ong, MD is an internal medicine physician with a practice address in Riverside, California, and NPI 1265416739, issued on Nov 30, 2005. Check the license (California G69360, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Iwan Sing-Djwan Ong
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- G69360 CA
Self-reported in NPPES; status is on the state search - Practice location
- 10800 Magnolia Ave, Riverside, CA 92505
- Phone
- (866) 984-7483
- Enumerated
- Nov 30, 2005
- Record last updated
- Dec 1, 2021 (not updated in 5 years: call before relying on the address or phone)
- Fax
- (626) 405-4600
- Medicare enrollment
- Enrolled (PECOS I20090129000543); accepts Medicare assignment
- Medical or professional school
- Loma Linda University School Of Medicine, 1989
- 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 Iwan Sing-Djwan Ong in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license G69360Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
37% fewer Medicare Part D claims than the average internal medicine physician in 2024
1,995 Medicare Part D claims for 720 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 6% of claims. 20 claims were for opioids.
Most prescribed
- Atorvastatin Calcium306 claims
- Omeprazole95 claims
- Levothyroxine Sodium69 claims
- Alendronate Sodium53 claims
- Pantoprazole Sodium50 claims
- Meloxicam47 claims
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).
Iwan Sing-Djwan Ong among 17,696 internal medicine physician records in California
Iwan Sing-Djwan Ong, MD 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 2005, is newer than 0% of them.
- NPI issued2005 · 0% of these records are older, 95% newer
- In a Medicare fileYes · 79% of these records are
- In the CMS Doctors and Clinicians fileYes · 63% of these records are
- Graduated1989 · median 2004 among the 11,065 with a school on file
- Record last updated2021 · 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
- Humera Rana, M.D.Riverside, CA 925051801982632
- Terence Shum, MDRiverside, CA 925051124195946
- Harneet Singh, MDRiverside, CA 925051114094943
- Shahram Soltanzadeh, M.D.Riverside, CA 925051700953528
Common questions
What is Iwan Sing-Djwan Ong, MD's NPI number?
Iwan Sing-Djwan Ong, MD's National Provider Identifier (NPI) is 1265416739, issued on Nov 30, 2005. An NPI identifies a provider in billing; it is not a license.
Where is Iwan Sing-Djwan Ong, MD located?
The NPPES record lists a practice address at 10800 Magnolia Ave, Riverside, CA, 92505. Phone: (866) 984-7483. Providers update this record themselves, so call before visiting.
How can I verify Iwan Sing-Djwan Ong, MD's license?
NPPES lists California license number G69360, 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 Iwan Sing-Djwan Ong, MD prescribe under Medicare Part D?
In 2024, Iwan Sing-Djwan Ong, MD had 1,995 Medicare Part D claims for 720 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.