Alexander Chang, M.D.
NPI 1225356231 · Internal Medicine Physician · San Francisco, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Alexander Chang, M.D. is a Internal Medicine Physician provider in San Francisco, CA (NPI 1225356231).
Provider details
- NPI number
- 1225356231
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- A127376 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
16 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
849 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our .
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 302 | $152 |
| Acupuncture, Initial 15 Minutes97810 | 109 | $41 |
| Acupuncture, Each Additional 15 Minutes97811 | 109 | $31 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 97 | $105 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 87 | $156 |
| Physician Or Allowed Practitioner Re-Certification for Medicare-Covered Home Health Services Under a Home Health Plan of Care (patient Not Present), Including Contacts With Home Health Agency and Review of Reports of Patient Status Required By Physicians a |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 91 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 518 | 164 |
| Amlodipine Besylate | 287 | 93 |
| Losartan Potassium | 241 | 72 |
| Lisinopril | 170 | 53 |
| Metformin Hcl | 159 | 47 |
| Tamsulosin Hcl | 152 | 51 |
| Metoprolol Succinate |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$353 across 12 records (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2010-05-14
- Last updated
- 2023-07-27
- Certified
- 2023-07-27
Frequently asked questions
- What is Alexander Chang's NPI number?
- Alexander Chang's National Provider Identifier (NPI) is 1225356231, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Alexander Chang's specialty?
- Alexander Chang is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Alexander Chang located?
- Alexander Chang's practice location on file with NPPES is 909 Hyde St Ste 230, San Francisco, CA 94109-4845.
- What is Alexander Chang's phone number?
- The practice phone number listed in the NPPES registry for Alexander Chang is (415) 779-8332.
- Does Alexander Chang accept Medicare?
- Alexander Chang is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Alexander Chang's NPI active?
- Yes — Alexander Chang's NPI (1225356231) is active in the NPPES registry as of the last update on 2023-07-27.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.