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WILLEM XU MD
NPI 1013570480
Anesthesiology in Santa Ana, CA

Active since April 20, 2019PECOS EnrolledAccepts Medicare Assignment
400 N TUSTIN AVE, SANTA ANA, CA 92705(714) 619-5391 Get Directions Write a Review

NPPES record last updated: June 17, 2024. Verified against the NPPES registry weekly; last sync: October 25, 2026.

Record update history: Jun 17, 2024, Apr 20, 2019 (2 updates tracked since 2019).

About Willem Xu Md NPPES

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

WILLEM XU MD (NPI 1013570480) is an individual anesthesiology provider in Santa Ana, California, licensed in California (A187501) and active in the NPI registry since April 2019. He is enrolled in Medicare PECOS and is a graduate of Other (2020).

NPPES Registry Identity

NPI1013570480
Entity TypeIndividualMale
Primary Taxonomy207L00000X
Provider Legal NameWILLEM XUCredential: MD
Location Address400 N TUSTIN AVESanta Ana, CA 92705-3813
Mailing Address400 N Tustin AveSanta Ana, CA 92705-3813
Phone(714) 619-5391
Sole ProprietorNo
Medical School CMSOtherGraduated 2020
Enumeration DateApril 20, 2019
Last NPPES UpdateJune 17, 20242 updates tracked since enumeration
NPPES CertifiedJune 17, 2024
✔ NPI 1013570480 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyAnesthesiologyAllopathic & Osteopathic Physicians
Taxonomy Code207L00000X
License✔ Licensed in CA · A187501
Definition
An anesthesiologist is trained to provide pain relief and maintenance, or restoration, of a stable condition during and immediately following an operation or an obstetric or diagnostic procedure. The anesthesiologist assesses the risk of the patient undergoing surgery and optimizes the patient's condition prior to, during and after surgery. In addition to these management responsibilities, the anesthesiologist provides medical management and consultation in pain management and critical care medicine. Anesthesiologists diagnose and treat acute, long-standing and cancer pain problems; diagnose and treat patients with critical illnesses or severe injuries; direct resuscitation in the care of patients with cardiac or respiratory emergencies, including the need for artificial ventilation; and supervise post-anesthesia recovery.
400 N TUSTIN AVE, Santa Ana, CA 92705
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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

Willem Xu 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 ID2961948617
PECOS Enrollment IDI20240718002307
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 Willem Xu reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Allied Anesthesia Medical Group Inc
  • Reassigned Medicare billing, California enrollment
  • 420 clinicians in this Medicare group
No phone listed

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 9

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

DUSTIN G MORRIS MD
Anesthesiology
400 N TUSTIN AVE
SANTA ANA, CA 92705
Orange County (714) 619-5391
DR. LAWRENCE ONG M.D., M.ENG.
Anesthesiology
400 N TUSTIN AVE, SUITE 400
SANTA ANA, CA 92705
Orange County (800) 888-2186
JENNIFER FERRUFINO
Technician, Health Information (Assistant Record Technician)
400 N TUSTIN AVE
SANTA ANA, CA 92705
Orange County (714) 617-4886
JASON KIM DO
Anesthesiology
400 N TUSTIN AVE
SANTA ANA, CA 92705
Orange County (714) 619-5383
DR. JENNIFER E ENGSTROM MD
Anesthesiology
400 N TUSTIN AVE, SUITE 400
SANTA ANA, CA 92705
Orange County (949) 417-1825
EXECUTIVE HAND THERAPY, INC.
Clinic/Center (Physical Therapy)
400 N TUSTIN AVE, SUITE 401
SANTA ANA, CA 92705
Orange County (714) 564-8210
PAMELA JEAN JACOBSON LAC
Acupuncturist
400 N TUSTIN AVE, SUITE 380
SANTA ANA, CA 92705
Orange County (714) 730-2233
THE HEALING SANCTUARY SPA, INC
Acupuncturist
400 N TUSTIN AVE, SUITE 380
SANTA ANA, CA 92705
Orange County (714) 730-2233

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 Willem Xu's NPI number?

The NPI number for Willem Xu is 1013570480. It was assigned to this individual provider in the NPPES registry on April 20, 2019.

Where is Willem Xu located?

Willem Xu practices at 400 N Tustin Ave, Santa Ana, CA 92705. The listed phone number is (714) 619-5391.

What is Willem Xu's specialty?

The primary specialty registered for this NPI is Anesthesiology with taxonomy code 207L00000X.

Is Willem Xu enrolled in Medicare?

Yes. Willem Xu 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 Willem Xu's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Willem Xu reassigns Medicare benefits to Allied Anesthesia Medical Group Inc (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 Willem Xu'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 Willem Xu was last updated on June 17, 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.