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DR. NATHAN KHOA NGUYEN M.D.
NPI 1861636615
Internal Medicine in Walnut Creek, CA

Active since April 23, 2009PECOS EnrolledAccepts Medicare Assignment
1425 S MAIN ST, MEDICAL OFFICE BUILDING 1ST FLOOR, WALNUT CREEK, CA 94596(925) 295-4050 Get Directions Write a Review

NPPES record last updated: November 30, 2021. Verified against the NPPES registry weekly; last sync: October 25, 2026.

Record update history: Nov 30, 2021, Nov 11, 2021 (2 updates tracked since 2021).

About Dr. Nathan Khoa Nguyen M.d. NPPES

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

DR. NATHAN KHOA NGUYEN M.D. (NPI 1861636615) is an individual internal medicine provider in Walnut Creek, California, licensed in California (A107250) and active in the NPI registry since April 2009. He is enrolled in Medicare PECOS and is a graduate of State University Of Ny Upstate Medical University (2007).

NPPES Registry Identity

NPI1861636615
Entity TypeIndividualMale
Primary Taxonomy207R00000X
Provider Legal NameDR. NATHAN KHOA NGUYENCredential: M.D.
Location Address1425 S MAIN ST, MEDICAL OFFICE BUILDING 1ST FLOORWalnut Creek, CA 94596-5318
Mailing Address4867 W Sunset BlvdLos Angeles, CA 90027-5969 · (925) 295-4050
Phone(925) 295-4050
Sole ProprietorNo
Medical School CMSState University Of Ny Upstate Medical UniversityGraduated 2007
Enumeration DateApril 23, 2009
Last NPPES UpdateNovember 30, 20212 updates tracked since enumeration
NPPES CertifiedNovember 11, 2021
✔ NPI 1861636615 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses 2

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians
Taxonomy Code207R00000X
License✔ Licensed in CA · A107250
Definition
A physician who provides long-term, comprehensive care in the office and the hospital, managing both common and complex illness of adolescents, adults and the elderly. Internists are trained in the diagnosis and treatment of cancer, infections and diseases affecting the heart, blood, kidneys, joints and digestive, respiratory and vascular systems. They are also trained in the essentials of primary care internal medicine, which incorporates an understanding of disease prevention, wellness, substance abuse, mental health and effective treatment of common problems of the eyes, ears, skin, nervous system and reproductive organs.
Also ListedInternal Medicine · Critical Care MedicineTaxonomy 207RC0200X · License 154500 (OR)
1425 S MAIN ST, Walnut Creek, CA 94596
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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

Dr. Nathan Khoa Nguyen M.d. 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 ID9335271055
PECOS Enrollment IDI20100715000893
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 Nathan Nguyen reassigns Medicare billing to 1 organization. The organization bills Medicare for the services this provider delivers there.

Southern California Permanente Medical Group
238 mi
Health Maintenance Organization
9100 ROSEDALE HWY
Bakersfield, CA 93312
  • Reassigned Medicare billing, California enrollment
  • Also billed through NPI 1275756652 (California)
  • 5,228 clinicians in this Medicare group
NPI 1316572753 (877) 608-0044

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

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.

Critical care, first 30-74 minutes 99291
Critical care involves immediate and constant attention by a team of specially-trained health professionals. It's for patients with life-threatening conditions, requiring first 30-74 minutes of intense monitoring and treatment.
16 services12 patients

Physician Visit Costs CMS claims · ZIP area

Typical Medicare office-visit costs in the 94596 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
$153.83 typical visit price
range $69.00 – $202.35
Typical copayment $38.45 (range $17.25 – $50.58)
Most-billed visit code 99204
Established Patient
$119.48 typical visit price
range $23.44 – $166.46
Typical copayment $29.87 (range $5.86 – $41.61)
Most-billed visit code 99214
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 20

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

BROOK ANDREW WOOLLEY M.D.
Emergency Medicine
1425 S MAIN ST, EMERGENCY MEDICINE DEPARTMENT
WALNUT CREEK, CA 94596
Contra Costa County (925) 295-5100
DR. THOMAS CRESANTE D.O.
Hospitalist
1425 S MAIN ST, KAISER PERMANENTE WALNUT CREEK ATTN: HBS DEPT
WALNUT CREEK, CA 94596
Contra Costa County (925) 295-4643
SARA WON MD
Obstetrics & Gynecology
1425 S MAIN ST
WALNUT CREEK, CA 94596
Contra Costa County (925) 295-4040
KAISER PERMANENTE
General Acute Care Hospital
1425 S MAIN ST
WALNUT CREEK, CA 94596
Contra Costa County (925) 295-4000
MICHELLE CABLE VU CRNA
Nurse Anesthetist, Certified Registered
1425 S MAIN ST
WALNUT CREEK, CA 94596
Contra Costa County (925) 295-4000
DR. JESUS GIL JIMENEZ MD
Surgery (Vascular Surgery)
1425 S MAIN ST
WALNUT CREEK, CA 94596
Contra Costa County (925) 295-4110
MR. EDWARD HAL PIECZENIK L.C.S.W.
Social Worker (Clinical)
1425 S MAIN ST
WALNUT CREEK, CA 94596
Contra Costa County (925) 295-5237
CARLOS A. CROMEYER MD
Psychiatry & Neurology (Neurology)
1425 S MAIN ST
WALNUT CREEK, CA 94596
Contra Costa County (925) 295-4000

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 Nathan Nguyen's NPI number?

The NPI number for Nathan Nguyen is 1861636615. It was assigned to this individual provider in the NPPES registry on April 23, 2009.

Where is Nathan Nguyen located?

Nathan Nguyen practices at 1425 S Main St Medical Office Building 1st Floor, Walnut Creek, CA 94596. The listed phone number is (925) 295-4050.

What is Nathan Nguyen's specialty?

The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.

Is Nathan Nguyen enrolled in Medicare?

Yes. Nathan Nguyen 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 Nathan Nguyen's services?

According to the CMS Revalidation Reassignment List (October 2026 release), Nathan Nguyen reassigns Medicare benefits to Southern California Permanente Medical Group (Bakersfield, 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 Nathan Nguyen'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 Nathan Nguyen was last updated on November 30, 2021. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 4 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.