2026 NPPES data Nurse Practitioner NPI 1538831490
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Diem Phuong Nguyen

Nurse Practitioner in San Jose, California. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.

Federal data — no proprietary rating. PlainDoctor publishes the actual CMS NPPES and Medicare records — NPI registration, specialty, practice location, and prescribing data — without a composite score or editorial opinion on top. Every field traces to a federal source.
Prescribing volume
488
Medicare Part D claims · 90 beneficiaries · Nurse Practitioner avg: 1K

What the federal data shows

Diem Phuong Nguyen filed 488 Medicare Part D claims in 2023 as a Nurse Practitioner in San Jose, California.

488
Part D claims, 2023

Every figure on this page comes straight from federal CMS records (NPPES, Medicare Part D, MIPS, Open Payments) — no proprietary rating or editorial opinion is applied.

Diem Phuong Nguyen's Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023 — across all CMS prescribers nationally

488 Top 38% higher than 62% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). Below this entry. 200–400: 182,923 prescribers (13%). Below this entry. 400–600: 90,619 prescribers (7%). This entry sits in this band. 600–800: 56,224 prescribers (4%). Above this entry. 800–1,000: 40,919 prescribers (3%). Above this entry. 1,000–1,200: 31,827 prescribers (2%). Above this entry. 1,200–1,400: 26,224 prescribers (2%). Above this entry. 1,400–1,600: 21,710 prescribers (2%). Above this entry. 1,600–1,800: 19,072 prescribers (1%). Above this entry. 1,800–2,000: 16,451 prescribers (1%). Above this entry. 2,000–2,200: 213,991 prescribers (16%). Above this entry. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

Each bar is a band; taller bars hold more prescribers. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.

Source CMS Medicare Part D Prescriber Public Use File · 2023

What does the federal data show about Diem Phuong Nguyen?

Quality data not reported

NPI registry status

Active

Issued 09/29/2021

NPI 1538831490

Primary specialty

Nurse Practitioner

High-volume

87,227 US NPIs in this specialty

Medicare Part D claims

488 55% vs specialty avg

2023 prescription claims

Specialty avg: 1,084

Specialty distribution in California

How Nurse Practitioner compares to other specialties among California providers

California providers

Nurse Practitioner share within California

1. Nurse Practitioner42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Nurse Practitioner share within California

Specialty board-certification context

Estimated specialty board-certified rate — Nurse Practitioner (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Nurse Practitioner ABMS/AOA estimate

Est. board-certified rate (Nurse Practitioner) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Nurse Practitioner) — ABMS / AOA estimate

The Merit-based Incentive Payment System (MIPS) scores providers 0–100 across four performance categories: Quality, Cost, Promoting Interoperability, and Improvement Activities, weighted under 42 CFR §414.1380. Reporting is voluntary for many small practices, so absence of a MIPS score is not a quality signal.

Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus continuous Maintenance of Certification cycles. Verify any individual provider's status through certificationmatters.org (ABMS) or osteopathic.org (AOA).

Diem Phuong Nguyen appears in the CMS NPPES registry as a Nurse Practitioner provider at 255 N WHITE RD STE 200, San Jose, CA, 95127, with a listed phone of (408) 503-7600. NPI 1538831490 was issued on 09/29/2021. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Nguyen most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D records for calendar year 2023 show 488 prescription claims written by this provider, covering 90 Medicare beneficiaries and totaling roughly $97K in drug spend. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Nurse Practitioner is a high-volume specialty nationwide, with 87,227 enrolled providers across 56 states and an average of 1,084 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline. Important: PlainDoctor is a directory of publicly available government data, not medical advice, a malpractice database, or a quality rating. Inclusion here does not imply a recommendation, and absence of complaints or sanctions on this page does not mean none exist — always verify credentials through the NPPES NPI Registry, your state medical board, and the ABMS or AOA before making healthcare decisions.

Practice Address

255 N WHITE RD STE 200
San Jose, CA 95127

Provider Details

NPI 1538831490
Specialty Nurse Practitioner
Gender Female
NPI Issued 09/29/2021

License & disciplinary context — California MBC 2023 annual report

Aggregate state board data only — NOT a determination of any individual provider's status. The figures below describe statewide disciplinary activity across all ~150K California medical licensees in 2023 — they are NOT specific to Diem Phuong Nguyen. To verify Diem Phuong Nguyen's current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.

576
Total board actions, California 2023
Across 556 cases
3.84
Actions per 1,000 licensees
California statewide rate
probation
Most common action type
186 cases

MBC publishes annual disciplinary statistics as part of public-record reporting under each state's Administrative Procedure Act. See the full breakdown by action type and year on the California disciplinary trends page. Cross-checked against FSMB U.S. Medical Regulatory Trends.

Medicare Part D Prescribing Data

CMS Medicare Part D prescriber-level data for calendar year 2023.

488
Total Claims
$97K
Total Drug Cost
90
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
1,029
Total Day Supply
30,072
Generic Drug Cost
$13K
Antibiotic Claims
17

Patient Demographics

Average Patient Age
77.7 years
Avg HCC Risk Score
2.68
Gender Split
57% female / 43% male
Age Distribution
<65: 11, 65-74: 23, 75-84: 26, 85+: 30

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

What Diem Phuong Nguyen prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Atorvastatin Calcium
32
Lisinopril
22
Eliquis
Apixaban
18
Tamsulosin Hcl
16
Trazodone Hcl
15
Alendronate Sodium
14
Amlodipine Besylate
14
Spiriva Handihaler
Tiotropium Bromide
14
Metoprolol Succinate
13
Donepezil Hcl
12

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Nurse Practitioner Overview

How Diem Phuong Nguyen fits within the Nurse Practitioner landscape nationally.

87,227
Nurse Practitioner Providers in US
56
States with Nurse Practitioner
1,084
Avg Claims per Provider

Diem Phuong Nguyen's 488 claims are below the specialty average of 1,084.

Nearby Nurse Practitioner Providers in California

Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Nguyen.

Compare Nurse Practitioner nationally: see state-by-state distribution →

Before you book an appointment

Use this federal record as your verification checklist, not as a recommendation.

  • Confirm the NPI record is current in the official CMS registry — providers update their own NPPES details, and moves can lag. Verify this NPI
  • Check the active license and any disciplinary history with the California medical board — federal registration is not a license check. Credential verification guide
  • Weigh a second option: compare this provider with a nearby Nurse Practitioner peer on Medicare volume and prescribing patterns. Compare providers

Medicare Part D and MIPS figures describe practice patterns in federal programs only — they are not quality ratings, and PlainDoctor does not rate, rank, or recommend providers.

Frequently Asked Questions

What is Diem Phuong Nguyen's specialty?
Diem Phuong Nguyen specializes in Nurse Practitioner and practices in San Jose, California.
How much does Diem Phuong Nguyen prescribe under Medicare Part D?
In 2023, Diem Phuong Nguyen wrote 488 Medicare Part D claims totaling $97K in drug costs for 90 beneficiaries.
Where is Diem Phuong Nguyen located?
Diem Phuong Nguyen is located at 255 N WHITE RD STE 200, San Jose, CA, 95127. Phone: (408) 503-7600.
What is Diem Phuong Nguyen's NPI number?
Diem Phuong Nguyen's National Provider Identifier (NPI) is 1538831490, issued on 09/29/2021.
How many Nurse Practitioner providers are there in the US?
There are 87,227 Nurse Practitioner providers across 56 states in the US. The average Nurse Practitioner provider writes 1,084 Medicare Part D claims per year.
What drugs does Diem Phuong Nguyen prescribe most often?
Based on 2023 Medicare Part D data, Diem Phuong Nguyen's most frequently prescribed drugs include Atorvastatin Calcium, Lisinopril, Eliquis. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Diem Phuong Nguyen accept Medicare?
Diem Phuong Nguyen appears in CMS Medicare data with 488 Part D claims and 90 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Diem Phuong Nguyen's credentials?
Diem Phuong Nguyen's NPI is 1538831490. You can verify this through the NPPES NPI Registry, check state medical board records, and confirm board certification through the ABMS or AOA.

Data Sources

Provider Directory
CMS National Plan and Provider Enumeration System (NPPES), download.cms.gov/nppes, updated monthly. Contains NPI, specialty, credentials, and practice location.
Specialty Classification
NUCC Health Care Provider Taxonomy (nucc.org), the industry standard for classifying provider specialties in Medicare and Medicaid billing.
Prescribing Data
CMS Medicare Part D Prescriber Public Use File (2023). Includes claims, drug costs, beneficiaries, and opioid prescribing rates.
Limitations
Provider data is self-reported to CMS. Prescribing data reflects Medicare Part D only and does not include commercial insurance, Medicaid, or cash prescriptions. Claims below 11 beneficiaries are suppressed by CMS for privacy.

See our complete data methodology for details on how we collect and process government data.

Data as of April 2026 (NPPES) / 2023 (Medicare Part D). Source: Centers for Medicare & Medicaid Services (CMS).

Disclaimer: Data from CMS NPPES and Medicare Part D. PlainDoctor does not rate or rank providers. Provider information is self-reported and may not be current. Always verify information directly with the provider. About · Methodology