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GILLIAN LEE HSIEH MD
NPI 1063765576
Obstetrics & Gynecology in Mountain View, CA

Active since October 22, 2012PECOS EnrolledAccepts Medicare Assignment
2490 HOSPITAL DR STE 111, MOUNTAIN VIEW, CA 94040(650) 934-7520 Get Directions Write a Review

NPPES record last updated: September 11, 2025. Verified against the NPPES registry weekly; last sync: November 01, 2026.

Record update history: Sep 11, 2025, Dec 10, 2018 (2 updates tracked since 2018).

About Gillian Lee Hsieh Md NPPES

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

GILLIAN LEE HSIEH MD (NPI 1063765576) is an individual obstetrics & gynecology provider in Mountain View, California, licensed in California (A134657) and active in the NPI registry since October 2012. She is enrolled in Medicare PECOS and is a graduate of Baylor College Of Medicine (2011).

NPPES Registry Identity

NPI1063765576
Entity TypeIndividualFemale
Primary Taxonomy207V00000X
Provider Legal NameGILLIAN LEE HSIEHCredential: MD
Location Address2490 HOSPITAL DR STE 111Mountain View, CA 94040-4126
Mailing Address2350 W El Camino Real Fl 2Mountain View, CA 94040-6203
Phone(650) 934-7520
Sole ProprietorNo
Medical School CMSBaylor College Of MedicineGraduated 2011
Enumeration DateOctober 22, 2012
Last NPPES UpdateSeptember 11, 20252 updates tracked since enumeration
✔ NPI 1063765576 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyObstetrics & GynecologyAllopathic & Osteopathic Physicians
Taxonomy Code207V00000X
License✔ Licensed in CA · A134657
Definition
An obstetrician/gynecologist possesses special knowledge, skills and professional capability in the medical and surgical care of the female reproductive system and associated disorders. This physician serves as a consultant to other physicians and as a primary physician for women.
2490 HOSPITAL DR STE 111, Mountain View, CA 94040
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Other Identifiers 1

OtherBP10039750TX · Texas Physician In Training

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

Gillian Lee Hsieh 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.

PECOS PAC ID5991023327
PECOS Enrollment IDI20150416000170
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 Reassignment

Medicare enrollment records show Gillian Hsieh reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Sutter Bay Medical Foundation
1.0 mi
Ambulatory Surgical
715 ALTOS OAKS DR
Los Altos, CA 94024
NPI 1568851327 (650) 934-3526

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

Areas of Expertise CMS Part B claims 9

Services this provider delivered to Medicare fee-for-service patients, from the CMS Medicare utilization data. Higher counts generally reflect more experience with a service; care delivered outside Medicare is not included.

Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more 99214
This is a routine check-up for patients who have previously visited our clinic. It involves a comprehensive review of your health and any ongoing treatments. The consultation lasts between 30-39 minutes, allowing enough time to discuss any concerns.
104 services88 patients
Established patient office or other outpatient visit with high level of medical decision making, if using time, 40 minutes or more 99215
This service involves a follow-up appointment for existing patients, lasting between 40 to 54 minutes. During this time, your healthcare provider will assess your current health status, discuss any changes or concerns, review your treatment plan, and answer any questions you may have.
96 services68 patients
New patient office or other outpatient visit with a high level of medical decision making, if using time, 60 minutes or more 99205
This is a first-time patient visit where a healthcare professional spends 60-74 minutes with you. It involves a comprehensive evaluation, including your medical history and current health condition. They'll also advise on preventive health measures and formulate a treatment plan if needed.
70 services70 patients
Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more 99213
This is a routine visit for patients who have already been seen by the healthcare provider. During this approximately 20-29 minute appointment, your health status will be evaluated and any necessary treatments or tests will be discussed. It's a chance to address any health concerns you may have.
54 services49 patients
Imaging of lymph nodes during surgery 38900
Imaging of lymph nodes during surgery involves taking detailed pictures of your lymph nodes to help surgeons see and assess them in real-time. This procedure can aid in detecting disease, guiding treatment, and improving surgical precision.
38 services38 patients
Biopsy and removal of lymph nodes of abdominal cavity using an endoscope 38570
This procedure involves using a thin, flexible tool called an endoscope to examine and remove lymph nodes in the abdominal area. The endoscope is inserted through a small incision. It allows doctors to view and biopsy, or take samples of, any suspicious tissues for further testing.
31 services31 patients

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 94040 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.

New Patient
$156.67 typical visit price
range $70.37 – $206.04
Typical copayment $39.16 (range $17.59 – $51.51)
Most-billed visit code 99204
Established Patient
$86.56 typical visit price
range $23.96 – $169.60
Typical copayment $21.64 (range $5.99 – $42.40)
Most-billed visit code 99213
Amounts reflect what Medicare beneficiaries in this ZIP area are typically charged for office visits. Patients with other coverage should check their individual plans.

Other Providers at the Same Location NPPES 9

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

SIMRIT KAUR WARRING MD
Obstetrics & Gynecology (Gynecologic Oncology)
2490 HOSPITAL DR STE 111
MOUNTAIN VIEW, CA 94040
Santa Clara County (650) 934-7530
MRS. CASSANDRA MARTIN PA-C
Physician Assistant
2490 HOSPITAL DR STE 111
MOUNTAIN VIEW, CA 94040
Santa Clara County (650) 934-7530
SARAH DIANE PIAZZA PA-C
Physician Assistant (Surgical)
2490 HOSPITAL DR STE 111
MOUNTAIN VIEW, CA 94040
Santa Clara County (650) 934-7520
BRIANNE JOHANNA-LOPICCOLO ROSS FNP
Nurse Practitioner (Family)
2490 HOSPITAL DR STE 111
MOUNTAIN VIEW, CA 94040
Santa Clara County (650) 560-6581
SHANNON DEE DONEGAN PA-C
Physician Assistant (Surgical)
2490 HOSPITAL DR STE 111
MOUNTAIN VIEW, CA 94040
Santa Clara County (650) 934-7530
MISS ERICA WITEK PA-C
Physician Assistant (Surgical)
2490 HOSPITAL DR STE 111
MOUNTAIN VIEW, CA 94040
Santa Clara County (650) 934-7530
DR. JESSICA SUZANNE ZIGMAN M.D.
Obstetrics & Gynecology (Urogynecology and Reconstructive Pelvic Surgery)
2490 HOSPITAL DR STE 111
MOUNTAIN VIEW, CA 94040
Santa Clara County (650) 934-7530
SARAH SANCHES PA-C
Physician Assistant (Surgical)
2490 HOSPITAL DR STE 111
MOUNTAIN VIEW, CA 94040
Santa Clara County (650) 934-7530

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 Gillian Hsieh's NPI number?

The NPI number for Gillian Hsieh is 1063765576. It was assigned to this individual provider in the NPPES registry on October 22, 2012.

Where is Gillian Hsieh located?

Gillian Hsieh practices at 2490 Hospital Dr Ste 111, Mountain View, CA 94040. The listed phone number is (650) 934-7520.

What is Gillian Hsieh's specialty?

The primary specialty registered for this NPI is Obstetrics & Gynecology with taxonomy code 207V00000X.

Is Gillian Hsieh enrolled in Medicare?

Yes. Gillian Hsieh 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 organization bills Medicare for Gillian Hsieh's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Gillian Hsieh reassigns Medicare benefits to Sutter Bay Medical Foundation (Los Altos, CA). The 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 Gillian Hsieh'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 Gillian Hsieh was last updated on September 11, 2025. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 13 months 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.