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

DR. JOHN T TSAI M.D.
NPI 1376527366
Pediatrics - Adolescent Medicine in Fairfax, VA

Active since December 02, 2005
3650 JOSEPH SIEWICK DR, SUITE 101, FAIRFAX, VA 22033(703) 391-0900(703) 391-2919 Get Directions Write a Review

NPPES record last updated: July 13, 2026. Verified against the NPPES registry weekly; last sync: August 16, 2026.

About Dr. John T Tsai M.d. NPPES

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

DR. JOHN T TSAI M.D. (NPI 1376527366) is an individual adolescent medicine provider in Fairfax, Virginia, licensed in Virginia (0101238865) and active in the NPI registry since December 2005.

NPPES Registry Identity

NPI1376527366
Entity TypeIndividualMale
Primary Taxonomy2080A0000X
Provider Legal NameDR. JOHN T TSAICredential: M.D.
Location Address3650 JOSEPH SIEWICK DR, SUITE 101Fairfax, VA 22033-1710
Mailing Address3650 Joseph Siewick Dr, Suite 101Fairfax, VA 22033-1710 · (703) 391-0900 · Fax (703) 391-2919
Phone(703) 391-0900
Fax(703) 391-2919
Sole ProprietorNo
Enumeration DateDecember 2, 2005
Last NPPES UpdateJuly 13, 2026
✔ NPI 1376527366 is a valid, active identifier and passes the ISO check-digit test.

Specialties & Licenses

★ Primary SpecialtyPediatrics · Adolescent MedicineAllopathic & Osteopathic Physicians
Taxonomy Code2080A0000X
License✔ Licensed in VA · 0101238865
Definition
A pediatrician who specializes in adolescent medicine is a multi-disciplinary healthcare specialist trained in the unique physical, psychological and social characteristics of adolescents, their healthcare problems and needs.
3650 JOSEPH SIEWICK DR, Fairfax, VA 22033
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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.

THUY PHUONG THI VO M.D.
Family Medicine
3650 JOSEPH SIEWICK DR, 400
FAIRFAX, VA 22033
Fairfax County (703) 391-2020
KATHERINE BOOKER PT
Physical Therapist
3650 JOSEPH SIEWICK DR, SUITE 308
FAIRFAX, VA 22033
Fairfax County (703) 716-4794
DR. LAURA E. BYRNES M.D.
Pediatrics
3650 JOSEPH SIEWICK DR, STE 101
FAIRFAX, VA 22033
Fairfax County (703) 391-0900
DR. HEON SOO YI M.D.
Family Medicine
3650 JOSEPH SIEWICK DR, SUITE 400
FAIRFAX, VA 22033
Fairfax County (703) 391-2020
VICTORIA LESSINGER MERKEL MD
Family Medicine
3650 JOSEPH SIEWICK DR, STE 400
FAIRFAX, VA 22033
Fairfax County (703) 391-2020
BRENT R AIN MD
Orthopaedic Surgery
3650 JOSEPH SIEWICK DR, SUITE 300
FAIRFAX, VA 22033
Fairfax County (703) 391-0111
SANDY L. CHUNG M.D.
Pediatrics
3650 JOSEPH SIEWICK DR, STE 101
FAIRFAX, VA 22033
Fairfax County (703) 391-0900
DR. PETER STEPHEN ROSS MD
Internal Medicine (Endocrinology, Diabetes & Metabolism)
3650 JOSEPH SIEWICK DR, #305
FAIRFAX, VA 22033
Fairfax County (703) 648-1831

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 John Tsai's NPI number?

The NPI number for John Tsai is 1376527366. It was assigned to this individual provider in the NPPES registry on December 2, 2005.

Where is John Tsai located?

John Tsai practices at 3650 Joseph Siewick Dr Suite 101, Fairfax, VA 22033. The listed phone number is (703) 391-0900.

What is John Tsai's specialty?

The primary specialty registered for this NPI is Pediatrics, specializing in Adolescent Medicine, with taxonomy code 2080A0000X.

When was this NPI record last updated?

The NPPES record for John Tsai was last updated on July 13, 2026. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 40 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.