SON LAM NGUYEN M.D.
NPI 1114119526
Internal Medicine in Fairfield, CA
About Son Lam Nguyen M.d. NPPES
Official registry information on file with the National Plan and Provider Enumeration System.
SON LAM NGUYEN M.D. (NPI 1114119526) is an individual internal medicine provider in Fairfield, California, licensed in California (A100779) and active in the NPI registry since August 2007. He is enrolled in Medicare PECOS and is a graduate of Other (2004).
NPPES Registry Identity
Specialties & Licenses
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
Son Lam 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.
Medicare Billing Reassignments
3Medicare enrollment records show Son Nguyen reassigns Medicare billing to 3 organizations. Each organization bills Medicare for the services this provider delivers there; the nearest is listed first.
Vallejo, CA 94589
- Reassigned Medicare billing, California enrollment
- 20,078 clinicians in this Medicare group
Antioch, CA 94509
- Reassigned Medicare billing, California enrollment
- Medicare enrollment name: Galen Inpatient Physicians PC
- 962 clinicians in this Medicare group
Greenbrae, CA 94904
- Reassigned Medicare billing, California enrollment
- 82 clinicians in this Medicare group
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 7
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.
Physician Visit Costs CMS claims · ZIP area
Typical Medicare office-visit costs in the 94533 ZIP code area, from fee-for-service claims. These are area statistics, not this provider’s prices; actual charges vary by service and coverage.
Medicare Quality Performance CMS QPP · MIPS
Performance in the CMS Quality Payment Program: the MIPS final score across four weighted categories, and the individual quality measures reported to Medicare.
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.
FAIRFIELD, CA 94533
FAIRFIELD, CA 94533
FAIRFIELD, CA 94533
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 Son Nguyen's NPI number?
The NPI number for Son Nguyen is 1114119526. It was assigned to this individual provider in the NPPES registry on August 10, 2007.
Where is Son Nguyen located?
Son Nguyen practices at 1525 Webster St A, Fairfield, CA 94533. The listed phone number is (707) 423-9484.
What is Son Nguyen's specialty?
The primary specialty registered for this NPI is Internal Medicine with taxonomy code 207R00000X.
Is Son Nguyen enrolled in Medicare?
Yes. Son 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 organizations bill Medicare for Son Nguyen's services?
According to the CMS Revalidation Reassignment List (October 2026 release), Son Nguyen reassigns Medicare benefits to 3 organizations: Permanente Medical Group Inc (Vallejo, CA), Galen Inpatient Physician Inc. (Antioch, CA) and Marin Hospitalist Medical Group, Inc. (Greenbrae, CA). Each 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 Son 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 Son Nguyen was last updated on October 18, 2008. NPI Profile syncs weekly with the NPPES registry data releases published by CMS. This NPI record was last updated 18 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.
# Son Lam Nguyen, M.D. · NPI 1114119526
Internal Medicine physician in Fairfield, California. Individual provider, active in the CMS NPPES registry since August 10, 2007.
## Identity
- **NPI:** 1114119526 (Entity type: Individual)
- **Enumerated:** August 10, 2007
- **Primary specialty:** Internal Medicine · taxonomy 207R00000X
- **State license:** A100779 (California)
- **Sole proprietor:** No
## Practice location
- **Address:** 1525 WEBSTER ST, A, Fairfield, CA 94533-4997
- **Phone:** (707) 423-9484
## Medicare
- **Medicare:** Enrolled (PECOS); accepts Medicare assignment
- **Ordering & referring:** eligible for Part B labs & imaging, durable medical equipment, home health, power mobility devices
- **Bills Medicare through:** 3 organizations under Medicare reassignment (form CMS-855R): Permanente Medical Group Inc (NPI 1336222397, Vallejo, CA); Galen Inpatient Physician Inc. (NPI 1083658223, Antioch, CA); Marin Hospitalist Medical Group, Inc. (NPI 1023041753, Greenbrae, CA) · CMS Revalidation Reassignment List, October 2026 release
- **Medical school:** Other, class of 2004
## Record status
- **NPPES last updated:** October 18, 2008
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Source: [NPI Profile](https://npiprofile.com/npi/1114119526) · Data from the CMS NPPES public registry.