Recently Updated NPI Information — some details in this NPI profile have been updated in the NPI registry within the last 60 days.

THERESA THANH NGOC NGUYEN MD INC
NPI 1750667192
Internal Medicine in Santa Ana, CA

Q: What is Theresa Thanh Ngoc Nguyen MD Inc's NPI number?

The NPI number for Theresa Thanh Ngoc Nguyen MD Inc is 1750667192. It was assigned to this organization in the NPPES registry on October 31, 2011.

Q: What is Theresa Thanh Ngoc Nguyen MD Inc's specialty?

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

Active since October 31, 2011

5030 WESTMINSTER AVE, SANTA ANA, CA 92703(714) 775-8090(657) 251-0494 Get Directions Write a Review

NPPES record last updated: October 23, 2026. Verified against the NPPES registry weekly; last sync: November 01, 2026.

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About Theresa Thanh Ngoc Nguyen Md Inc NPPES

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

THERESA THANH NGOC NGUYEN MD INC (NPI 1750667192) is a healthcare organization registered as an internal medicine in Santa Ana, California and active in the NPI registry since October 2011. The organization lists Theresa Thanh Ngoc Nguyen, Physician In Charge, as its authorized official.

NPPES Registry Identity

NPI1750667192

Entity TypeOrganization

Primary Taxonomy207R00000X

Legal Business NameTHERESA THANH NGOC NGUYEN MD INC

Location Address5030 WESTMINSTER AVESanta Ana, CA 92703-1151

Mailing Address5030 Westminster AveSanta Ana, CA 92703-1151 · (714) 775-8090 · Fax (657) 251-0494

Phone(714) 775-8090

Fax(657) 251-0494

Organization SubpartNo

Authorized OfficialTheresa Thanh Ngoc NguyenPhysician In Charge · (714) 775-8090

Enumeration DateOctober 31, 2011

Last NPPES UpdateOctober 23, 2026

NPPES CertifiedOctober 23, 2026

✔ NPI 1750667192 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyInternal MedicineAllopathic & Osteopathic Physicians

Taxonomy Code207R00000X

License✔ Licensed in CA · A61129

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.

5030 WESTMINSTER AVE, Santa Ana, CA 92703

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Medicare Participation & PECOS CMS

Medicare enrollment, revalidation and the clinicians who bill Medicare through this organization, from CMS.

Medicare Enrollment Status

✔

Enrolled in Medicare (PECOS)

Theresa Thanh Ngoc Nguyen Md Inc is registered in the CMS Provider Enrollment, Chain and Ownership System (PECOS).

Medicare Revalidation Due Date

Revalidation due by December 31, 2026

Medicare-enrolled providers and suppliers confirm their enrollment information with CMS on a set cycle, every 5 years for most and every 3 years for medical equipment suppliers. CMS sets the due date for each enrollment.

StateEnrollment IDDue date

StateCaliforniaEnrollment IDO20120501000230Non-DME Part B · Clinic/Group PracticeDue dateDecember 31, 2026

Source: CMS Revalidation Due Date List, October 2026 release.

Clinicians Billing Medicare Through This Organization

Medicare enrollment records show 3 clinicians reassign Medicare billing to Theresa Thanh Ngoc Nguyen MD Inc, which bills Medicare for the services they deliver. Of these, 3 practice at this address. They are listed nearest first.

Clinicians, nearest first (3)

Tam Nguyen

Nurse Practitioner

NPI 1407562853

5030 WESTMINSTER AVE
Santa Ana, CA 92703

(714) 775-8090

✔ PECOSSame address

Thai Nguyen, M.D.

Internal Medicine

NPI 1467547042

5030 WESTMINSTER AVE
Santa Ana, CA 92703

(714) 775-8090

✔ PECOS✔ Accepts MedicareSame address

Theresa Thanh Nguyen, M.D.

Internal Medicine

NPI 1003893801

5030 WESTMINSTER AVE
Santa Ana, CA 92703

(714) 775-8090

✔ PECOS✔ Accepts MedicareSame address

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

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 Theresa Thanh Ngoc Nguyen MD Inc's NPI number?

The NPI number for Theresa Thanh Ngoc Nguyen MD Inc is 1750667192. It was assigned to this organization in the NPPES registry on October 31, 2011.

Where is Theresa Thanh Ngoc Nguyen MD Inc located?

Theresa Thanh Ngoc Nguyen MD Inc is located at 5030 Westminster Ave, Santa Ana, CA 92703. The listed phone number is (714) 775-8090.

What is Theresa Thanh Ngoc Nguyen MD Inc's specialty?

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

Is Theresa Thanh Ngoc Nguyen MD Inc enrolled in Medicare?

Yes. Theresa Thanh Ngoc Nguyen MD Inc is registered in the Medicare PECOS enrollment system.

When is Theresa Thanh Ngoc Nguyen MD Inc's Medicare revalidation due?

According to the CMS Revalidation Due Date List (October 2026 release), the Medicare Non-DME Part B enrollment for this organization (California, Clinic/Group Practice) is due for revalidation by December 31, 2026. Medicare providers and suppliers revalidate their enrollment every 5 years, and medical equipment suppliers every 3 years. Confirm current requirements with your Medicare Administrative Contractor.

How many clinicians bill Medicare through Theresa Thanh Ngoc Nguyen MD Inc?

According to the CMS Revalidation Reassignment List (October 2026 release), 3 clinicians reassign their Medicare billing to Theresa Thanh Ngoc Nguyen MD Inc, in Internal Medicine and Nurse Practitioner. A 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 the clinician's services. Of these, 3 practice at this address. Reassignment records can lag staffing changes; confirm a current affiliation with the organization.

When was this NPI record last updated?

The NPPES record for Theresa Thanh Ngoc Nguyen MD Inc was last updated on October 23, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 13 days 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.