2026 NPPES data Allergy Physician NPI 1982625430 M.D
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ROGER NGUYEN, M.D

Allergy Physician in GARDEN GROVE, 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
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)
What the federal data reveals: ROGER NGUYEN, M.D is a Allergy Physician ([object Object]) practicing in GARDEN GROVE, California with a Medicare Part D prescribing footprint of 496 claims across 120 beneficiaries — 20% brand-name prescribing . Industry payments of $2.2K across 73 transactions are disclosed under CMS Open Payments (Sunshine Act).

What stands out: ROGER NGUYEN, M.D filed 496 Medicare Part D claims in 2023 across GARDEN GROVE, California. Every figure on this page comes straight from federal CMS records, with no proprietary rating applied.

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).

ROGER NGUYEN, M.D at a glance

Quality data not reported

NPI registry status

Active

Issued 07/21/2006

NPI 1982625430

Primary specialty

Allergy Physician

Niche

1,019 US NPIs in this specialty

Medicare Part D claims

496 34% vs specialty avg

2023 prescription claims

Specialty avg: 755

Specialty distribution in California

How Allergy Physician compares to other specialties among California providers

California providers

Allergy Physician share within California

1. Allergy Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Allergy Physician share within California

Specialty board-certification context

Estimated specialty board-certified rate — Allergy Physician (ABMS / AOA reference)

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

Est. board-certified rate (Allergy Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Allergy Physician) — 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).

ROGER NGUYEN, M.D is a Allergy Physician provider practicing in GARDEN GROVE, California, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: M.D. NPI: 1982625430. This profile includes practice location, specialty classification, and organizational affiliations from the CMS provider registry. Provider information is self-reported to CMS and updated monthly.

ROGER NGUYEN, M.D appears in the CMS NPPES registry as a 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. 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 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. 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.

Allergy Physician is a narrow specialty nationwide, with 1,019 enrolled providers across 49 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

9746 WESTMINSTER AVE STE A
GARDEN GROVE, CA 92844

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%
Specialty average (est.)

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.

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.

1,019
Allergy Physician Providers in US
49
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.

Compare Allergy Physician nationally: see state-by-state distribution →

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 1,019 Allergy Physician providers across 49 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

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