NPI Portal NPI Lookup & Verification

Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum Sole proprietor

Dr. Mark Joshua Chang, DO

Hematology & Oncology Physician in Upland, CA · enumerated 2019.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1861954182

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Registry record

Entity type Individual (Type 1)
Name Dr. Mark Joshua Chang
Credential DO
Sex Male
Practice address Upland, CA, 91786
Phone (909) 949-2242
Fax (909) 981-5783
Enumeration date Apr 4, 2019
Last updated in NPPES Jul 8, 2026

Street address withheld: NPPES sole-proprietor addresses can be home addresses. See our data policy.

Taxonomy & licenses

207R00000X Internal Medicine Physician Allopathic & Osteopathic Physicians · License DO3131 (NV) Secondary
207RH0003X Hematology & Oncology Physician Allopathic & Osteopathic Physicians · License 20A24887 (CA) Primary
207RX0202X Medical Oncology Physician Allopathic & Osteopathic Physicians · License 20A24887 (CA) Secondary
DO · Doctor of Osteopathic Medicine: A fully licensed physician trained in osteopathic medical schools, with the same practice rights as an MD. About the DO credential

Other identifiers

Identifier Type State Issuer
DO3131 Other NV NV MEDICAL BOARD OF OSTEOPATHIC MEDICINE

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

Read the full guide → Validate an NPI →

Frequently asked questions

What specialty is Mark Chang?
Mark Chang is registered in NPPES with the primary taxonomy of Hematology & Oncology Physician. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.
Is this the official NPI registry?
No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

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Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2026-07-08.