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RYAN CHANG
NPI 1164985263
Internal Medicine - Medical Oncology in San Mateo, CA

Active since April 08, 2019PECOS Enrolled
218 DE ANZA BLVD, SAN MATEO, CA 94402(415) 514-7520 Get Directions Write a Review

NPPES record last updated: August 28, 2024. Verified against the NPPES registry weekly; last sync: October 25, 2026.

About Ryan Chang NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

RYAN CHANG (NPI 1164985263) is an individual medical oncology provider in San Mateo, California, licensed in California (A179941) and active in the NPI registry since April 2019. He is enrolled in Medicare PECOS.

NPPES Registry Identity

NPI1164985263
Entity TypeIndividualMale
Primary Taxonomy207RX0202X
Provider Legal NameRYAN CHANG
Location Address218 DE ANZA BLVDSan Mateo, CA 94402-3913
Mailing Address1 Hawthorne St Unit 20fSan Francisco, CA 94105-3983 · (415) 937-3662
Phone(415) 514-7520
Sole ProprietorNo
Enumeration DateApril 8, 2019
Last NPPES UpdateAugust 28, 2024
NPPES CertifiedAugust 28, 2024
✔ NPI 1164985263 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal Medicine · Medical OncologyAllopathic & Osteopathic Physicians
Taxonomy Code207RX0202X
License✔ Licensed in CA · A179941
Definition
An internist who specializes in the diagnosis and treatment of all types of cancer and other benign and malignant tumors. This specialist decides on and administers therapy for these malignancies as well as consults with surgeons and radiotherapists on other treatments for cancer.
218 DE ANZA BLVD, San Mateo, CA 94402
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Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Ryan Chang is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignments

3

Medicare enrollment records show Ryan Chang reassigns Medicare billing to 3 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

Regents Of The University Of California
18 mi
Endocrinology, Diabetes & Metabolism
505 PARNASSUS AVE
San Francisco, CA 94143
  • Reassigned Medicare billing, California enrollment
  • 2,112 clinicians in this Medicare group
NPI 1376613943 (415) 353-2350
University Of California San Francisco
18 mi
Surgery
400 PARNASSUS AVE, MCB 300
San Francisco, CA 94143
  • Reassigned Medicare billing, California enrollment
  • 5,645 clinicians in this Medicare group
NPI 1346329380 (415) 353-2161
Ucsf Medical Group Business Services
18 mi
Internal Medicine
400 PARNASSUS AVE
San Francisco, CA 94122
  • Reassigned Medicare billing, California enrollment
  • 5,544 clinicians in this Medicare group
NPI 1477624104 (415) 353-2808

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 94402 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient
$202.35 typical visit price
range $69.00 – $202.35
Typical copayment $50.58 (range $17.25 – $50.58)
Most-billed visit code 99205
Established Patient
$119.48 typical visit price
range $23.44 – $166.46
Typical copayment $29.87 (range $5.86 – $41.61)
Most-billed visit code 99214
Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Other Providers at the Same Location NPPES 17

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

KENT MARC-JOSEF ADLER M.D.
Internal Medicine (Hematology & Oncology)
218 DE ANZA BLVD
SAN MATEO, CA 94402
San Mateo County (650) 341-9131
DR. DANIEL RENGSTORFF M.D.
Internal Medicine (Gastroenterology)
218 DE ANZA BLVD
SAN MATEO, CA 94402
San Mateo County (650) 341-9131
KATRINA SESLINE LCSW, MPH
Social Worker (Clinical)
218 DE ANZA BLVD
SAN MATEO, CA 94402
San Mateo County (415) 420-6389
ELHAM VOSOUGHI M.D.
Internal Medicine (Hematology & Oncology)
218 DE ANZA BLVD
SAN MATEO, CA 94402
San Mateo County (650) 341-9131
DONALD TIMOTHY SCHAUKOWITCH N.P.
Nurse Practitioner (Family)
218 DE ANZA BLVD
SAN MATEO, CA 94402
San Mateo County (650) 341-9131
MATTHEW HYUN JOON LEE D.O.
Internal Medicine (Medical Oncology)
218 DE ANZA BLVD
SAN MATEO, CA 94402
San Mateo County (650) 341-9131
MRS. SUZANNE HEIDI KEENAN APRN
Nurse Practitioner
218 DE ANZA BLVD
SAN MATEO, CA 94402
San Mateo County (650) 341-9131
DR. KAREN CHEE M.D.
Internal Medicine (Hematology & Oncology)
218 DE ANZA BLVD
SAN MATEO, CA 94402
San Mateo County (650) 341-9131

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Ryan Chang's NPI number?

The NPI number for Ryan Chang is 1164985263. It was assigned to this individual provider in the NPPES registry on April 8, 2019.

Where is Ryan Chang located?

Ryan Chang practices at 218 De Anza Blvd, San Mateo, CA 94402. The listed phone number is (415) 514-7520.

What is Ryan Chang's specialty?

The primary specialty registered for this NPI is Internal Medicine, specializing in Medical Oncology, with taxonomy code 207RX0202X.

Is Ryan Chang enrolled in Medicare?

Yes. Ryan Chang is registered in the Medicare PECOS enrollment system.

Which organizations bill Medicare for Ryan Chang's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Ryan Chang reassigns Medicare benefits to 3 organizations: Regents Of The University Of California (San Francisco, CA), University Of California San Francisco (San Francisco, CA) and Ucsf Medical Group Business Services (San Francisco, CA). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Ryan Chang's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

When was this NPI record last updated?

The NPPES record for Ryan Chang was last updated on August 28, 2024. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 2 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.