Geraldine Tan, MD
NPI 1699744086 · Hospitalist Physician · Walnut Creek, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Geraldine Tan, MD is a Hospitalist Physician provider in Walnut Creek, CA (NPI 1699744086).
Provider details
- NPI number
- 1699744086
- Entity type
- Individual
- Primary specialty
- Hospitalist PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- A81859 (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 tenure38% of score
20 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
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.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-03-16
- Last updated
- 2015-09-29
Frequently asked questions
- What is Geraldine Tan's NPI number?
- Geraldine Tan's National Provider Identifier (NPI) is 1699744086, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Geraldine Tan's specialty?
- Geraldine Tan is listed in the NPPES registry with a primary specialty of Hospitalist Physician (Allopathic & Osteopathic Physicians).
- Where is Geraldine Tan located?
- Geraldine Tan's practice location on file with NPPES is 1220 Rossmoor Pkwy, Walnut Creek, CA 94595-2501.
- What is Geraldine Tan's phone number?
- The practice phone number listed in the NPPES registry for Geraldine Tan is (925) 947-3393.
- Does Geraldine Tan accept Medicare?
- Geraldine Tan is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Geraldine Tan's NPI active?
- Yes — Geraldine Tan's NPI (1699744086) is active in the NPPES registry as of the last update on 2015-09-29.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.