Ruby Chang, M.D.
NPI 1164459335 · Diagnostic Radiology Physician · Walnut Creek, CA
Enrolled with Medicare as Practitioner - Diagnostic Radiology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Ruby Chang, M.D. is a Diagnostic Radiology Physician provider in Walnut Creek, CA (NPI 1164459335).
Provider details
- NPI number
- 1164459335
- Entity type
- Individual
- Primary specialty
- Diagnostic Radiology PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Female
- Sole proprietor
- No
- License
- A81716 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
19 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
8,624 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) |
|---|---|---|
| Screening 3d Breast Mammography77063 | 3,410 | $54 |
| Screening Mammography77067 | 3,406 | $135 |
| Diagnostic Digital Breast Tomosynthesis, Unilateral Or Bilateral (list Separately in Addition to 77065 Or 77066)G0279 | 345 | $50 |
| Diagnostic Mammography of 1 Breast77065 | 240 | $133 |
| Limited Ultrasound Scan of 1 Breast76642 | 229 | $93 |
| Diagnostic Mammography of Both Breasts77066 | 205 |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$23 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
Registry dates
- Enumerated
- 2006-06-26
- Last updated
- 2015-04-02
Frequently asked questions
- What is Ruby Chang's NPI number?
- Ruby Chang's National Provider Identifier (NPI) is 1164459335, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Ruby Chang's specialty?
- Ruby Chang is listed in the NPPES registry with a primary specialty of Diagnostic Radiology Physician (Allopathic & Osteopathic Physicians).
- Where is Ruby Chang located?
- Ruby Chang's practice location on file with NPPES is 2125 Oak Grove Rd, Walnut Creek, CA 94598-2536.
- What is Ruby Chang's phone number?
- The practice phone number listed in the NPPES registry for Ruby Chang is (925) 296-7150.
- Does Ruby Chang accept Medicare?
- Ruby Chang is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Ruby Chang's NPI active?
- Yes — Ruby Chang's NPI (1164459335) is active in the NPPES registry as of the last update on 2015-04-02.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.