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WENDY SI M.D
NPI 1043674823
Pediatrics - Neonatal-Perinatal Medicine in Palo Alto, CA

Active since April 07, 2016PECOS Enrolled
725 WELCH RD, PALO ALTO, CA 94304(650) 497-8000 Get Directions Write a Review

NPPES record last updated: April 29, 2024. Verified against the NPPES registry weekly; last sync: October 25, 2026.

Record update history: Apr 29, 2024, Jun 6, 2019 (2 updates tracked since 2019).

About Wendy Si M.d NPPES

Official registry information on file with the National Plan and Provider Enumeration System.

WENDY SI M.D (NPI 1043674823) is an individual neonatal-perinatal medicine provider in Palo Alto, California, licensed in California (A162129) and active in the NPI registry since April 2016. She is enrolled in Medicare PECOS.

NPPES Registry Identity

NPI1043674823
Entity TypeIndividualFemale
Primary Taxonomy2080N0001X
Provider Legal NameWENDY SICredential: M.D
Location Address725 WELCH RDPalo Alto, CA 94304-1601
Mailing Address725 Welch RdPalo Alto, CA 94304-1601 · (650) 497-8000
Phone(650) 497-8000
Sole ProprietorNo
Enumeration DateApril 7, 2016
Last NPPES UpdateApril 29, 20242 updates tracked since enumeration
NPPES CertifiedApril 29, 2024
✔ NPI 1043674823 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 3

★ Primary SpecialtyPediatrics · Neonatal-Perinatal MedicineAllopathic & Osteopathic Physicians
Taxonomy Code2080N0001X
License✔ Licensed in CA · A162129
Definition
A pediatrician who is the principal care provider for sick newborn infants. Clinical expertise is used for direct patient care and for consulting with obstetrical colleagues to plan for the care of mothers who have high-risk pregnancies.
Also ListedPediatricsTaxonomy 208000000X · License A162129 (CA)
Also ListedHospitalistTaxonomy 208M00000X · License A162129 (CA)
725 WELCH RD, Palo Alto, CA 94304
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Other Names 1

Other Name (5)Wen Si Md

Medicare Participation & PECOS CMS

Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Wendy Si M.d is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Eligible to Order & Refer✔ Part B Labs & Imaging✔ Durable Medical Equipment✔ Home Health Agency✔ Power Mobility DevicesPer the CMS Ordering and Referring file. Eligibility means Medicare pays claims that this provider orders or refers for these categories.

Medicare Billing Reassignments

2

Medicare enrollment records show Wendy Si reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.

Lpch Medical Group Div Of Lucile
Same address
Children
725 WELCH RD
Palo Alto, CA 94304
  • Reassigned Medicare billing, California enrollment
  • 3,617 clinicians in this Medicare group
NPI 1417907940 (650) 498-6762
Stanford Health Care
0.2 mi
General Acute Care Hospital
300 PASTEUR DRIVE
Stanford, CA 94305
  • Reassigned Medicare billing, California enrollment
  • 4,258 clinicians in this Medicare group
NPI 1437292927 (650) 723-4000

Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

Other Providers at the Same Location NPPES 20

Providers registered at the same practice address, or within the immediate area, according to the NPPES registry.

EIRI INENAGA MS, OTR/L
Occupational Therapist (Pediatrics)
725 WELCH RD
PALO ALTO, CA 94304
Santa Clara County (650) 497-8218
WENDY LEIGH ADAMS ARNP
Nurse Practitioner (Neonatal)
725 WELCH RD
PALO ALTO, CA 94304
Santa Clara County (650) 497-8000
KEVIN WEI-HAN CHI MD
Pediatrics
725 WELCH RD
PALO ALTO, CA 94304
Santa Clara County (650) 497-8000
ASHEEN RAMA MD
Anesthesiology (Pediatric Anesthesiology)
725 WELCH RD
PALO ALTO, CA 94304
Santa Clara County (650) 497-8000
CRYSTAL LEE MACKALL MD
Pediatrics (Pediatric Hematology-Oncology)
725 WELCH RD
PALO ALTO, CA 94304
Santa Clara County (650) 497-8000
KRISTI LYNNE O'CONNOR OT
Occupational Therapist
725 WELCH RD
PALO ALTO, CA 94304
Santa Clara County (650) 497-8000
LAUREN GENNA ROOS NP
Nurse Practitioner
725 WELCH RD
PALO ALTO, CA 94304
Santa Clara County (650) 497-8000
SHALINI MITTAL MD
Hospitalist
725 WELCH RD
PALO ALTO, CA 94304
Santa Clara County (650) 497-8000

Frequently Asked Questions NPPES & CMS

Common questions about this NPI record, answered from the official NPPES registry and CMS datasets shown on this page.

What is Wendy Si's NPI number?

The NPI number for Wendy Si is 1043674823. It was assigned to this individual provider in the NPPES registry on April 7, 2016. The provider is also known as Wen Si MD.

Where is Wendy Si located?

Wendy Si practices at 725 Welch Rd, Palo Alto, CA 94304. The listed phone number is (650) 497-8000.

What is Wendy Si's specialty?

The primary specialty registered for this NPI is Pediatrics, specializing in Neonatal-Perinatal Medicine, with taxonomy code 2080N0001X.

Is Wendy Si enrolled in Medicare?

Yes. Wendy Si is registered in the Medicare PECOS enrollment system.

Which organizations bill Medicare for Wendy Si's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Wendy Si reassigns Medicare benefits to 2 organizations: Lpch Medical Group Div Of Lucile (Palo Alto, CA) and Stanford Health Care (Stanford, CA). Each reassignment is filed with Medicare on form CMS-855R, signed by both the clinician and the organization, and lets the organization bill Medicare and receive payment for Wendy Si's services. Reassignment records can lag staffing changes; confirm current arrangements with the organization.

When was this NPI record last updated?

The NPPES record for Wendy Si was last updated on April 29, 2024. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 2 years ago. If this record has changed at CMS more recently, you can request an on-demand re-check against the live CMS registry, directly from this page.