XIN SI MD
NPI 1639581804
Pediatrics - Pediatric Pulmonology in Palo Alto, CA
About Xin Si Md NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
XIN SI MD (NPI 1639581804) is an individual pediatric pulmonology provider in Palo Alto, California, licensed in California (A154969) and active in the NPI registry since May 2014. She is enrolled in Medicare PECOS and is a graduate of Baylor College Of Medicine (2014).
NPPES Registry Identity
Specialties & Licenses 3
Medicare Participation & PECOS CMS
Medicare enrollment, assignment, billing reassignment, and ordering and referring status from CMS.
Medicare Enrollment Status
Enrolled in Medicare and accepts Medicare assignment
Xin Si Md is registered in PECOS and agrees to accept the Medicare-approved amount as full payment. Medicare patients are not billed beyond the standard deductible and coinsurance.
Medicare Billing Reassignments
2Medicare enrollment records show Xin Si reassigns Medicare billing to 2 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Palo Alto, CA 94304
- Reassigned Medicare billing, California enrollment
- 3,617 clinicians in this Medicare group
Stanford, CA 94305
- Reassigned Medicare billing, California enrollment
- 4,258 clinicians in this Medicare group
Source: CMS Revalidation Reassignment List, October 2026 release. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.
Referred Medical Equipment & Supplies CMS DME claims 2
Durable medical equipment, devices and supplies this provider ordered from DME suppliers for patients, from Medicare fee-for-service claims.
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.
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 Xin Si's NPI number?
The NPI number for Xin Si is 1639581804. It was assigned to this individual provider in the NPPES registry on May 22, 2014.
Where is Xin Si located?
Xin Si practices at 725 Welch Rd, Palo Alto, CA 94304. The listed phone number is (650) 497-8000.
What is Xin Si's specialty?
The primary specialty registered for this NPI is Pediatrics, specializing in Pediatric Pulmonology, with taxonomy code 2080P0214X.
Is Xin Si enrolled in Medicare?
Yes. Xin Si is registered in the Medicare PECOS system and accepts Medicare assignment, which means accepting the Medicare-approved amount as payment in full for covered services.
Which organizations bill Medicare for Xin Si's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Xin 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 Xin 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 Xin Si was last updated on April 27, 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.
# Xin Si, MD · NPI 1639581804
Pediatric Pulmonology physician in Palo Alto, California. Individual provider, active in the CMS NPPES registry since May 22, 2014.
## Identity
- **NPI:** 1639581804 (Entity type: Individual)
- **Enumerated:** May 22, 2014
- **Primary specialty:** Pediatrics - Pediatric Pulmonology · taxonomy 2080P0214X
- **State license:** A154969 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 725 WELCH RD, Palo Alto, CA 94304-1601
- **Phone:** (650) 497-8000
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 2 organizations under Medicare reassignment (form CMS-855R): Lpch Medical Group Div Of Lucile (NPI 1417907940, Palo Alto, CA); Stanford Health Care (NPI 1437292927, Stanford, CA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Baylor College Of Medicine, class of 2014
## Record status
- **NPPES last updated:** April 27, 2024
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Source: [NPI Profile](https://npiprofile.com/npi/1639581804) · Data from the CMS NPPES public registry.