NPI registry status
Active
2026 NPPES data Allergy Physician NPI 1982625430 M.D
Verify on CMS → Roger Nguyen, M.D
Allergy Physician in Garden Grove, California.
This profile is drawn from the federal National Provider Identifier Registry (CMS NPPES), which lists more than 7 million U.S. healthcare providers - including 1,017 in Allergy Physician, and covers specialty classification, practice address, and Medicare Part D prescribing data when reported. According to CMS, every field reflects the provider's official federal registration, see our methodology.
Federal data, no proprietary rating.
We show these CMS records as-is - no composite score, no star rating, no editorial opinion layered on top.
Prescribing volume
496
Medicare Part D claims · 120 beneficiaries · Allergy Physician avg: 755
Generic prescribing
80%
generic claims · 20% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$2.2K
73 payments · CMS Open Payments (Sunshine Act)
Source: CMS Medicare Part D Prescriber Public Use File, 2023
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Roger Nguyen, M.D filed 496 Medicare Part D claims in 2023 as a Allergy Physician in Garden Grove, California, prescribing 80% generic.
- 496
- Part D claims, 2023
- 80%
- generic prescribing
- $2.2K
- industry payments (Sunshine Act)
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.
Roger Nguyen, M.D's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
496 Top 38% higher than 62% of 1,370,886 prescribers
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
◑
Board-eligible specialty (heuristic, not verified)
Roger Nguyen, M.D practices in an ABMS-board-eligible specialty but we don't have enough CMS-participation signals to confirm active board-certified status. Consult CertificationMatters.org (the official ABMS public lookup).
What does the federal data show about Roger Nguyen, M.D?
Quality data not reportedPrimary specialty
Allergy Physician
Medicare Part D claims
496 34% vs specialty avg
Specialty distribution in California
How Allergy Physician compares to other specialties among California providers
Board certification
Not published by CMS
CMS does not publish a per-provider board-certification field in NPPES. PlainDoctor does not have a reliable per-specialty certification rate to show for Allergy Physician. Verify directly:
How MIPS and board certification work
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).
Roger Nguyen, M.D appears in the CMS NPPES registry as an Allergy Physician provider holding M.D credentials at 9746 WESTMINSTER AVE STE A, Garden Grove, CA, 92844, with a listed phone of (714) 638-4433. NPI 1982625430 was issued on 07/21/2006.
Medicare Part D records for calendar year 2023 show 496 prescription claims written by this provider, covering 120 Medicare beneficiaries and totaling roughly $172K in drug spend, split 20% brand-name and 80% generic by claim count.
Allergy Physician is a narrow specialty nationwide, with 1,017 enrolled providers across 50 states and an average of 755 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
Provider Details
| NPI | 1982625430 |
|---|---|
| Specialty | Allergy Physician |
| Credentials | M.D |
| Gender | Male |
| NPI Issued | 07/21/2006 |
Industry payments received (2024) - CMS Open Payments transparency data
The federal Physician Payments Sunshine Act (part of the Affordable Care Act) requires drug and medical-device manufacturers + group purchasing organizations to publicly report payments and other transfers of value to physicians and teaching hospitals. The data below covers 2024 for Roger Nguyen, M.D. Source: openpaymentsdata.cms.gov.
Total received
$2.2K
Largest payer
GENZYME CORPORATION
Most common payment type
Food and Beverage
Industry payments are not necessarily indicators of bias, they include research funding, consulting fees for evidence-based work, royalties for inventions, food at conferences, and similar items. The disclosure exists for transparency. Read our methodology for how we interpret this data.
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 Roger Nguyen, M.D. To verify Roger Nguyen, M.D'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.
Brand vs generic prescribing mix · Typical
Roger Nguyen, M.D - brand share 20.0%
Allergy Physician average
20% brand-name claims vs 80% generic, on 496 2023 Medicare Part D claims.
The federal Medicare Part D Generic Dispensing Rate national benchmark sits near 90% generic / 10% brand for primary-care prescribers, per CMS Office of the Actuary 2024 estimates. Higher brand share is common in specialty prescribing where generic equivalents are not available.
Medicare Part D Prescribing Data
CMS Medicare Part D prescriber-level data for calendar year 2023.
496
Total Claims
$172K
Total Drug Cost
120
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 689
- Total Day Supply
- 19,981
- Brand vs Generic
- 20% brand / 80% generic
- Brand Drug Cost
- $159K
- Generic Drug Cost
- $13K
Patient Demographics
- Average Patient Age
- 72.2 years
- Avg HCC Risk Score
- 1.27
- Gender Split
- 56% female / 44% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Roger Nguyen, M.D prescribes most
Top Medicare Part D drugs by claim count, 2023
- Levocetirizine Dih…
Levocetirizine Dihydrochloride
121 claims
- Triamcinolone Acet…
Triamcinolone Acetonide
52 claims
- Montelukast Sodium 44
Montelukast Sodium
44 claims
- Azelastine Hcl 38
Azelastine Hcl
38 claims
- Mometasone Furoate 36
Mometasone Furoate
36 claims
- Ipratropium Bromide 25
Ipratropium Bromide
25 claims
- Dupixent Pen 24
Dupixent Pen
24 claims
- Albuterol Sulfate … 18
Albuterol Sulfate Hfa
18 claims
| Drug | Claims |
|---|---|
| Levocetirizine Dihydrochloride | 121 |
| Triamcinolone Acetonide | 52 |
| Montelukast Sodium | 44 |
| Azelastine Hcl | 38 |
| Mometasone Furoate | 36 |
| Ipratropium Bromide | 25 |
| Dupixent Pen Dupilumab | 24 |
| Albuterol Sulfate Hfa Albuterol Sulfate | 18 |
| Spiriva Respimat Tiotropium Bromide | 15 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Allergy Physician Overview
How Roger Nguyen, M.D fits within the Allergy Physician landscape nationally.
1,017
Allergy Physician Providers in US
50
States with Allergy Physician
755
Avg Claims per Provider
Roger Nguyen, M.D's 496 claims are below the specialty average of 755.
Nearby Allergy Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Nguyen.
Dr. Shilpi Anand
M.D.
Walnut Creek, CA
Dr. Paula Ardron
MD
Bakersfield, CA
Dr. Tania Aung
M.D.
Vacaville, CA
Dr. Julia Bae
MD
Bakersfield, CA
Dr. Jeffrey Balduzzi
M.D.
Stockton, CA
Compare Allergy Physician 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 Allergy Physician 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.
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Understanding Medicare Claims Data
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Frequently Asked Questions
What is Roger Nguyen, M.D's specialty? ▼
Roger Nguyen, M.D specializes in Allergy Physician and practices in Garden Grove, California. Credentials: M.D.
How much does Roger Nguyen, M.D prescribe under Medicare Part D? ▼
In 2023, Roger Nguyen, M.D wrote 496 Medicare Part D claims totaling $172K in drug costs for 120 beneficiaries.
Where is Roger Nguyen, M.D located? ▼
Roger Nguyen, M.D is located at 9746 WESTMINSTER AVE STE A, Garden Grove, CA, 92844. Phone: (714) 638-4433.
What is Roger Nguyen, M.D's NPI number? ▼
Roger Nguyen, M.D's National Provider Identifier (NPI) is 1982625430, issued on 07/21/2006.
Does Roger Nguyen, M.D prescribe more brand-name or generic drugs? ▼
Roger Nguyen, M.D's prescribing is 20% brand-name and 80% generic drugs by claim count, with $159K in brand drug costs.
How many Allergy Physician providers are there in the US? ▼
There are 1,017 Allergy Physician providers across 50 states in the US. The average Allergy Physician provider writes 755 Medicare Part D claims per year.
What drugs does Roger Nguyen, M.D prescribe most often? ▼
Based on 2023 Medicare Part D data, Roger Nguyen, M.D's most frequently prescribed drugs include Levocetirizine Dihydrochloride, Triamcinolone Acetonide, Montelukast Sodium. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Roger Nguyen, M.D accept Medicare? ▼
Roger Nguyen, M.D appears in CMS Medicare data with 496 Part D claims and 120 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Roger Nguyen, M.D's credentials? ▼
Roger Nguyen, M.D's NPI is 1982625430 with credentials M.D. 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
View source datasets and methodology notes
- 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
Compiled from official public sources by the PlainDoctor editorial team.
Every figure on PlainDoctor is rendered directly from the federal CMS NPPES registry, Medicare Part D, MIPS, and Open Payments records, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of May 2026.