Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

Karen Chang, DO

Individual provider Gastroenterology Physician · NPI 1861855439

Karen Chang, DO practises Internal Medicine in Rialto, California. Graduated from Lake Erie College of Osteopathic Medicine, Erie in 2016, 10 years ago. Practices with San Bernardino Gastroenterology Associates Inc, a 7-clinician group and accepts Medicare assignment. Licensed in California.

Years since qualifying
10
Trained at
Lake Erie College of Osteopathic Medicine, Erie
Licensed in
CA
In the registry since
2016
What do these letters mean?
DO — Doctor of Osteopathic Medicine
A fully licensed physician, trained like an MD with additional musculoskeletal training. Equivalent practice rights in all 50 states.

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Practice location Address checks out

2006 N Riverside Ave Ste B
Rialto, CA 92377-4697
Phone: (909) 644-4035
Fax: (909) 881-0668
Show map & directions

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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Gastroenterology Physician (primary) Taxonomy 207RG0100X · Licence 20A16468 (CA)

Record details

NPI number1861855439
Entity typeIndividual (Type 1)
GenderFemale
Credentials DO
Sole proprietorNo
NPI enumeratedMarch 31, 2016
Last updated in NPPESJanuary 18, 2024
Certification dateJanuary 18, 2024

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyINTERNAL MEDICINE
Medical schoolLAKE ERIE COLLEGE OF OSTEOPATHIC MEDICINE, ERIE
Graduated 2016 (10 years in practice)
Group practice San Bernardino Gastroenterology Associates Inc — 7 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

Procedures

From CMS Care Compare, which counts the procedures a clinician billed to Original Medicare and Medicare Advantage over a recent 12-month period. CMS reports a fixed list of common procedures, so this is not everything the clinician does. Counts of 10 or fewer are given as a range, because CMS withholds small numbers.

Colonoscopy 80 times · 74th percentile
Upper gastrointestinal (GI) endoscopy for acid reflux 86 times · 74th percentile

The percentile compares how often this clinician performed the procedure with other clinicians who performed it, as CMS calculates it. It measures volume, not outcomes or skill.

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients154
Services billed 329 a service is one billed item, such as a visit, a test or a procedure
Average patient age71

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $787 34 payments · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician. Those with a page here are linked.

Colleagues at San Bernardino Gastroenterology Associates Inc

Clinicians the CMS Doctors & Clinicians file lists under the same group practice.

Other providers in Rialto