David Shi-Ann Chang, M.D.
NPI 1639330806ActiveIndividual· Internal Medicine· Stanford, CA
Internal Medicine (M.D.) in Stanford, California, trained at Tufts University School of Medicine (class of 2008). Their prescriptions cost Medicare Part D more than their services did: $134,173 for 1,171 claims, against $12,412 paid for services in 2024. Access Pro Medical, LLC was the largest of 2 companies reporting payments in 2025, $65.79 in all, mostly food and beverage.
Overview
| NPI | 1639330806 |
|---|---|
| Status | Active |
| Entity type | Individual |
| Credential | M.D. |
| Sole proprietor | No |
| NPI issued | Jun 20, 2008 |
| Last updated in NPPES | Apr 18, 2024 |
| Certified by provider | Apr 18, 2024 |
Specialties and licenses
| Taxonomy | Code | License | State |
|---|---|---|---|
| Internal Medicine Primary | 207R00000X | C149397 | CA |
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 - Internal Medicine (CA) |
|---|---|
| Accepts assignment | Yes (participating) |
Medicare services in 2024
| Medicare patients | 156 |
|---|---|
| Services billed | 227 across 9 procedure codes |
| Paid by Medicare | $12,412 |
Part D prescriptions in 2024
| Prescriptions (claims) | 1,171 · 2,943 30-day fills |
|---|---|
| Patients | 178 |
| Total drug cost | $134,173 |
| Generic share | 87% of claims |
Education and affiliations
| Medical school | Tufts University School of Medicine |
|---|---|
| Graduation year | 2008 |
| Medicare specialty | Internal Medicine |
| Telehealth | Offers telehealth |
Medical group
- Stanford Health CareStanford, CA · 3,122 clinicians
Hospital affiliations
- Sentara Careplex HospitalHampton, VA
- Stanford Health CareStanford, CA
- Stanford Health Care Tri-ValleyPleasanton, CA
Industry payments (Open Payments)
- 2025$65.79 · 3 payments from 2 companies
Top paying companies in 2025
| Company | Amount | Payments |
|---|---|---|
| Access Pro Medical, LLC | $45.11 | 2 |
| Aimmune Therapeutics, Inc. | $20.68 | 1 |
What the 2025 payments were for
- Food and Beverage$65.79 · 3 payments
Receiving payments does not imply wrongdoing. What Open Payments covers ·original records
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All 394 internal medicine physicians in Stanford · All internal medicine physicians in California