Ralph Defronzo, MD
NPI 1851408843 · Endocrinology, Diabetes & Metabolism Physician · San Antonio, TX
Enrolled with Medicare as Practitioner - Endocrinology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Ralph Defronzo, MD is a Endocrinology, Diabetes & Metabolism Physician provider in San Antonio, TX (NPI 1851408843).
Provider details
- NPI number
- 1851408843
- Entity type
- Individual
- Primary specialty
- Endocrinology, Diabetes & Metabolism PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- H7531 (TX)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure33% of score
19 yrs in NPPES registry
- Profile completeness33% of score
100% of core fields populated
- Practice footprint20% of score
1 documented practice location
- Open Payments transparency13% of score
Has Open Payments disclosures (2024)
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 methodology.
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$142,981 across 71 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
- 2006-08-24
- Last updated
- 2011-05-02
Frequently asked questions
- What is Ralph Defronzo's NPI number?
- Ralph Defronzo's National Provider Identifier (NPI) is 1851408843, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Ralph Defronzo's specialty?
- Ralph Defronzo is listed in the NPPES registry with a primary specialty of Endocrinology, Diabetes & Metabolism Physician (Allopathic & Osteopathic Physicians).
- Where is Ralph Defronzo located?
- Ralph Defronzo's practice location on file with NPPES is 701 S Zarzamora St, San Antonio, TX 78207-5209.
- What is Ralph Defronzo's phone number?
- The practice phone number listed in the NPPES registry for Ralph Defronzo is (210) 358-7500.
- Does Ralph Defronzo accept Medicare?
- Ralph Defronzo is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Ralph Defronzo's NPI active?
- Yes — Ralph Defronzo's NPI (1851408843) is active in the NPPES registry as of the last update on 2011-05-02.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.