Carolyn Siu
NPI 1679304448 · Physician Assistant · San Mateo, CA
Enrolled with Medicare as Practitioner - Physician Assistant · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Carolyn Siu is a Physician Assistant provider in San Mateo, CA (NPI 1679304448).
Provider details
- NPI number
- 1679304448
- Entity type
- Individual
- Primary specialty
- Physician AssistantPhysician Assistants & Advanced Practice Nursing Providers
- Sex
- Female
- Sole proprietor
- No
- License
- PA65879 (CA)
Specialties & taxonomies
Physician Assistants & Advanced Practice Nursing Providers
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
1 yr 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
- 2024-08-12
- Last updated
- 2026-01-13
- Certified
- 2026-01-13
Frequently asked questions
- What is Carolyn Siu's NPI number?
- Carolyn Siu's National Provider Identifier (NPI) is 1679304448, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Carolyn Siu's specialty?
- Carolyn Siu is listed in the NPPES registry with a primary specialty of Physician Assistant (Physician Assistants & Advanced Practice Nursing Providers).
- Where is Carolyn Siu located?
- Carolyn Siu's practice location on file with NPPES is 50 S San Mateo Dr Fl 4, San Mateo, CA 94401-3857.
- What is Carolyn Siu's phone number?
- The practice phone number listed in the NPPES registry for Carolyn Siu is (650) 652-8500.
- Does Carolyn Siu accept Medicare?
- Carolyn Siu is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Carolyn Siu's NPI active?
- Yes — Carolyn Siu's NPI (1679304448) is active in the NPPES registry as of the last update on 2026-01-13.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.