Karen Chang, DO
Gastroenterology Physician · Rialto, CA
Karen Chang, DO is a gastroenterology physician with a practice address in Rialto, California, and NPI 1861855439, issued on Mar 31, 2016. Check the license (California 20A16468, as entered in NPPES) on the Medical Board of California; the Medicare figures below come from public CMS files.
- Name
- Karen Chang
- Credential
- DO
- Primary taxonomy
- Gastroenterology Physician 207RG0100X
- License number
- 20A16468 CA
Self-reported in NPPES; status is on the state search - Practice location
- 2006 N Riverside Ave Ste B, Rialto, CA 92377
- Phone
- (909) 644-4035
- Enumerated
- Mar 31, 2016
- Record last updated
- Jan 18, 2024
- Fax
- (909) 881-0668
- Medicare enrollment
- Enrolled (PECOS I20200527000683); accepts Medicare assignment
- Medical or professional school
- Lake Erie College Of Osteopathic Medicine, Erie, 2016
- Entity
- Type 1 · individual
8 nearest gastroenterology physician records → All 2,140 in California → Look up another NPI →
Also registered at 2006 N Riverside Ave Ste B
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Gabriela Armenta, PA-CPhysician Assistant1699503342
- Carlos Buitrago, MDGastroenterology Physician1710481445
- Ira Pauline Santos, PA-CPhysician Assistant1518659382
Verify Karen Chang in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersMedical Board of California
Search for license 20A16468Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
93% fewer Medicare Part D claims than the average gastroenterology physician in 2024
60 Medicare Part D claims for 39 beneficiaries, against an average of 811 among the 16,445 providers of this specialty who prescribed in Part D. Brand-name drugs were 18% of claims.
Most prescribed
- Pantoprazole Sodium12 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.
Industry payments in 2024: $950.17
45 payments; by number, the most common kind was food and beverage; the largest payer was Abbvie Inc. The 13,350 providers of this specialty with any payment received $5,015.95 on average. Payments are reported by manufacturers, not by the provider, and are not a sign of wrongdoing.
Source: CMS Open Payments, program year 2024 (openpaymentsdata.cms.gov); average among providers of this specialty with at least one payment.
Bills Medicare through one group practice
- San Bernardino Gastroenterology Associates IncRialto, CA
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Karen Chang among 2,140 gastroenterology physician records in California
Karen Chang, DO is one of 2,140 gastroenterology physician records with a practice address in California. 83% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2016, is newer than 88% of them.
- NPI issued2016 · 88% of these records are older, 9% newer
- In a Medicare fileYes · 83% of these records are
- In the CMS Doctors and Clinicians fileYes · 72% of these records are
- Graduated2016 · median 2002 among the 1,538 with a school on file
- Record last updated2024 · 60% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RG0100X and a California practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Gastroenterology Physician providers in California
There are 2,140 gastroenterology physician records in California.
All 2,140 in California → Every provider in Rialto → Gastroenterology Physician nationwide →
The 8 gastroenterology physician records with the nearest ZIP codes
- Kumaravelu Balasubramaniam, MDRialto, CA 923771134184708
- Carlos Buitrago, MDRialto, CA 923771710481445
- Victor Guharoy, MDRialto, CA 923771306259114
- Anas Kawayeh, M.D.Rialto, CA 923771821296591
- Albert Chang, MDRedlands, CA 923741790984805
- Khushal Stanisai, MDRedlands, CA 923741720019821
- Gary Wernick, MDRedlands, CA 923741033189808
- Bradley Collins, PA-CRedlands, CA 923731881791986
Common questions
What is Karen Chang, DO's NPI number?
Karen Chang, DO's National Provider Identifier (NPI) is 1861855439, issued on Mar 31, 2016. An NPI identifies a provider in billing; it is not a license.
Where is Karen Chang, DO located?
The NPPES record lists a practice address at 2006 N Riverside Ave Ste B, Rialto, CA, 92377. Phone: (909) 644-4035. Providers update this record themselves, so call before visiting.
How can I verify Karen Chang, DO's license?
NPPES lists California license number 20A16468, 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 Karen Chang, DO prescribe under Medicare Part D?
In 2024, Karen Chang, DO had 60 Medicare Part D claims for 39 beneficiaries; the average among gastroenterology physician prescribers was 811. 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.