Xin Si, MD
NPI 1639581804 · Pediatric Pulmonology Physician · Palo Alto, CA
Enrolled with Medicare as Practitioner - Pediatric Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Xin Si, MD is a Pediatric Pulmonology Physician provider in Palo Alto, CA (NPI 1639581804).
Provider details
- NPI number
- 1639581804
- Entity type
- Individual
- Primary specialty
- Pediatric Pulmonology PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- A154969 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
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
12 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
- 2014-05-22
- Last updated
- 2024-04-27
- Certified
- 2024-04-27
Frequently asked questions
- What is Xin Si's NPI number?
- Xin Si's National Provider Identifier (NPI) is 1639581804, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Xin Si's specialty?
- Xin Si is listed in the NPPES registry with a primary specialty of Pediatric Pulmonology Physician (Allopathic & Osteopathic Physicians).
- Where is Xin Si located?
- Xin Si's practice location on file with NPPES is 725 Welch Rd, Palo Alto, CA 94304-1601.
- What is Xin Si's phone number?
- The practice phone number listed in the NPPES registry for Xin Si is (650) 497-8000.
- Does Xin Si accept Medicare?
- Xin Si is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Xin Si's NPI active?
- Yes — Xin Si's NPI (1639581804) is active in the NPPES registry as of the last update on 2024-04-27.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.