Charles Y. Chang, MD
NPI 1942436886ActiveIndividual· Urology· Concord, CA
Urology (MD) with John Muir Physician Network, practicing in Concord, California. Their prescriptions cost Medicare Part D more than their services did: $381,707 for 1,021 claims, against $6,380 paid for services in 2024. Janssen Biotech, Inc. was the largest of 13 companies reporting payments in 2025, $848.56 in all, mostly food and beverage. Lists John Muir Medical Center - Concord Campus and 1 other hospital as hospital affiliations.
Overview
| NPI | 1942436886 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | MD |
| Sole proprietor | No |
| NPI issued | Jun 5, 2009 |
| Last updated in NPPES | Dec 12, 2024 |
| Certified by provider | Dec 12, 2024 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Urology Primary | 208800000X | C166684 | CA |
| Urology | 208800000X | MD60462997 | WA |
| Urology | 208800000X | 125054599 | IL |
| Urology | 208800000X | 314844 | NY |
Exclusion screening
| List | Result | Details |
|---|---|---|
| HHS-OIG LEIE · Nov 10, 2026 | No match | Checked by NPI and by name + state |
| North Carolina Medicaid · Nov 11, 2026 | No match | — |
| New York OMIG · Nov 11, 2026 | No match | — |
| Ohio Medicaid · Nov 11, 2026 | No match | — |
| Pennsylvania Medicheck · Nov 11, 2026 | No match | — |
| Washington HCA · Nov 11, 2026 | No match | — |
Official OIG search · How matching works ·Bulk check a roster
Medicare
| Enrollment (PECOS) | Enrolled Practitioner - Urology (CA); Practitioner - Urology (NY); Practitioner - Urology (WA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 46 |
|---|---|
| Services billed | 78 across 13 procedure codes |
| Paid by Medicare | $6,380 |
Part D prescriptions in 2024
| Prescriptions (claims) | 1,021 · 1,823 30-day fills |
|---|---|
| Patients | 249 |
| Total drug cost | $381,707 |
| Generic share | 83% of claims |
Education and affiliations
| Graduation year | 2008 |
|---|---|
| Medicare specialty | Urology |
| Telehealth | Offers telehealth |
Medical group
- John Muir Physician NetworkPleasant Hill, CA · 494 clinicians
Hospital affiliations
- John Muir Medical Center - Concord CampusConcord, CA
- John Muir Medical Center - Walnut Creek CampusWalnut Creek, CA
Industry payments (Open Payments)
- 2025$848.56 · 19 payments from 13 companies
- 2024$11.08 · 1 payment from 1 company
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Janssen Biotech, Inc. | $211.40 | 5 |
| Abbvie Inc. | $153.93 | 2 |
| Ferring Pharmaceuticals Inc. | $124.99 | 1 |
| Olympus America Inc. | $109.39 | 1 |
| Verity Pharmaceuticals Inc. | $53.98 | 2 |
What the 2025 payments were for
- Food and Beverage$813.50 · 18 payments
- Education$35.06 · 1 payment
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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