Tan Nguyen, MD
NPI 1003256843 · Internal Medicine Physician · Sunnyvale, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Tan Nguyen, MD is a Internal Medicine Physician provider in Sunnyvale, CA (NPI 1003256843).
Provider details
- NPI number
- 1003256843
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- A140731 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Student, Health Care
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
12 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
745 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 275 | $154 |
| Visit Complexity Inherent to Evaluation and Management Associated With Medical Care Services That Serve As the Continuing Focal Point for All Needed Health Care Services And/Or With Medical Care Services That Are Part of Ongoing Care Related to a Patient'SG2211 | 128 | $19 |
| Established Patient Office Or Other Outpatient Visit With Low Level OD Decision Making, If Using Time, 20 Minutes Or More99213 | 125 | $111 |
| Annual Wellness Visit, Includes a Personalized Prevention Plan of Service (pps), Subsequent VisitG0439 | 90 | $157 |
| Administration of Influenza Virus VaccineG0008 | 38 | $39 |
| Administration of Pneumococcal Vaccine |
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 53 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 292 | 94 |
| Losartan Potassium | 130 | 38 |
| Amlodipine Besylate | 122 | 39 |
| Tamsulosin Hcl | 75 | 24 |
| Rosuvastatin Calcium | 62 | 17 |
| Lisinopril | 60 | 21 |
| Metformin Hcl |
Practice location
Mailing address
Registry dates
- Enumerated
- 2013-06-25
- Last updated
- 2016-10-10
Frequently asked questions
- What is Tan Nguyen's NPI number?
- Tan Nguyen's National Provider Identifier (NPI) is 1003256843, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Tan Nguyen's specialty?
- Tan Nguyen is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Tan Nguyen located?
- Tan Nguyen's practice location on file with NPPES is 301 Old San Francisco Rd, Sunnyvale, CA 94086-6386.
- What is Tan Nguyen's phone number?
- The practice phone number listed in the NPPES registry for Tan Nguyen is (408) 730-4360.
- Does Tan Nguyen accept Medicare?
- Tan Nguyen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Tan Nguyen's NPI active?
- Yes — Tan Nguyen's NPI (1003256843) is active in the NPPES registry as of the last update on 2016-10-10.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.