Allen Chang, MD
NPI 1588976567 · Emergency Medicine Physician · Tracy, CA
Enrolled with Medicare as Practitioner - Emergency Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Allen Chang, MD is a Emergency Medicine Physician provider in Tracy, CA (NPI 1588976567).
Provider details
- NPI number
- 1588976567
- Entity type
- Individual
- Primary specialty
- Emergency Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- Yes
- License
- C143700 (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
15 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
2 documented practice locations
- Medicare service volume (vs. specialty peers)25% of score
30 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) |
|---|---|---|
| Emergency Department Visit With High Level of Medical Decision Making99285 | 30 | $171 |
Typical Medicare-allowed amounts for these services range $171–$171 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 5 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Albuterol Sulfatebrand: Albuterol Sulfate Hfa | 22 | — |
| Prednisone | 19 | 19 |
| Cephalexin | 15 | 15 |
| Hydrocodone/Acetaminophenbrand: Hydrocodone-Acetaminophen | 12 | 12 |
| Ofloxacin | 12 | 12 |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means , never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$18 across 1 record (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
Additional practice locations (1)
- 751 S Bascom AveSan Jose, CA 95128-2699Phone: (408) 885-5000
Registry dates
- Enumerated
- 2010-07-08
- Last updated
- 2022-10-01
- Certified
- 2022-10-01
Frequently asked questions
- What is Allen Chang's NPI number?
- Allen Chang's National Provider Identifier (NPI) is 1588976567, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Allen Chang's specialty?
- Allen Chang is listed in the NPPES registry with a primary specialty of Emergency Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Allen Chang located?
- Allen Chang's practice location on file with NPPES is 1420 N Tracy Blvd, Tracy, CA 95376-3451.
- What is Allen Chang's phone number?
- The practice phone number listed in the NPPES registry for Allen Chang is (209) 835-1500.
- Does Allen Chang accept Medicare?
- Allen Chang is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Allen Chang's NPI active?
- Yes — Allen Chang's NPI (1588976567) is active in the NPPES registry as of the last update on 2022-10-01.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.