Vivian Nguyen, MD
NPI 1689869570 · Internal Medicine Physician · Westminster, CA
Enrolled with Medicare as Practitioner - Hospitalist · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Vivian Nguyen, MD is a Internal Medicine Physician provider in Westminster, CA (NPI 1689869570).
Provider details
- NPI number
- 1689869570
- Entity type
- Individual
- Primary specialty
- Internal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Female
- Sole proprietor
- No
- License
- 249741 (NY)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure25% of score
18 yrs in NPPES registry
- Profile completeness25% of score
100% of core fields populated
- Practice footprint15% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)25% of score
1,341 Medicare services, 2024 (ranked within specialty)
- Open Payments transparency10% of score
Has Open Payments disclosures (2024)
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 .
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) |
|---|---|---|
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 50 Minutes99233 | 1,105 | $120 |
| Hospital Discharge Day Management, More Than 30 Minutes99239 | 124 | $115 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 50 | $137 |
| Initial Hospital Care With Moderate Level of Medical Decision Making, If Using Time, at Least 75 Minutes99223 | 43 | $177 |
| New Patient Office Or Other Outpatient Visit With a High Level of Medical Decision Making, If Using Time, 60 Minutes Or More99205 | 19 | $236 |
Typical Medicare-allowed amounts for these services range $115–$236 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 41 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 72 | 24 |
| Losartan Potassium | 42 | 14 |
| Amlodipine Besylate | 38 | 11 |
| Apixabanbrand: Eliquis | 37 | 14 |
| Levofloxacin | 36 | 32 |
| Pantoprazole Sodium | 35 | 18 |
| Lisinopril |
Transparency — industry payments
Based on CMS Open Payments, 2024; not all care is captured.
$22 across 1 record (Open Payments 2024)
Open Payments discloses payments and transfers of value (meals, travel, consulting, research, royalties) from drug and device makers to providers. This is a transparency signal, not a verdict — such payments are legal and common, and their presence is neither an endorsement nor a criticism. Source: CMS Open Payments, program year 2024.
Practice location
Mailing address
Registry dates
- Enumerated
- 2007-09-13
- Last updated
- 2023-05-18
- Certified
- 2023-05-18
Frequently asked questions
- What is Vivian Nguyen's NPI number?
- Vivian Nguyen's National Provider Identifier (NPI) is 1689869570, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Vivian Nguyen's specialty?
- Vivian Nguyen is listed in the NPPES registry with a primary specialty of Internal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Vivian Nguyen located?
- Vivian Nguyen's practice location on file with NPPES is 8419 Westminster Blvd, Westminster, CA 92683-3308.
- What is Vivian Nguyen's phone number?
- The practice phone number listed in the NPPES registry for Vivian Nguyen is (714) 248-9558.
- Does Vivian Nguyen accept Medicare?
- Vivian Nguyen is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Vivian Nguyen's NPI active?
- Yes — Vivian Nguyen's NPI (1689869570) is active in the NPPES registry as of the last update on 2023-05-18.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.