2026 NPPES data Rheumatology Physician NPI 1538313648 M.D.
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Bao Quynh Huynh, M.D.

Rheumatology Physician in Orange, 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 6,181 in Rheumatology 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
436
Medicare Part D claims · 73 beneficiaries · Rheumatology Physician avg: 2K
Industry payments
$96.08
4 payments · CMS Open Payments (Sunshine Act)
Compiled from official public sources by the PlainDoctor editorial team.

What the federal data shows

Bao Quynh Huynh, M.D. filed 436 Medicare Part D claims in 2023 as a Rheumatology Physician in Orange, California.

436
Part D claims, 2023
Likely
board-certified (heuristic)

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.

Bao Quynh Huynh, M.D.'s Medicare Part D volume vs every U.S. prescriber

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

436 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. 2K+: 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

Board certification likely (heuristic, not verified)

Bao Quynh Huynh, M.D. practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 1 hospital affiliation - signals consistent with board-certified status. For verified board certification, see CertificationMatters.org (the official ABMS public lookup).

What does the federal data show about Bao Quynh Huynh, M.D.?

Quality data not reported

NPI registry status

Active

Issued 11/17/2008

NPI 1538313648

Primary specialty

Rheumatology Physician

Mid-sized

6,181 US NPIs in this specialty

Medicare Part D claims

436 79% vs specialty avg

2023 prescription claims

Specialty avg: 2,054

Specialty distribution in California

How Rheumatology Physician compares to other specialties among California providers

California providers

Largest specialties in California (% of in-state providers)

Behavior Technician - 17.3%Behavior Technician17.3%Marriage & Family Therapist - 5.5%Marriage & Family Therapist5.5%Student in an Organized Health Care Education/Training Program - 5%Student in an Organized Health Care Education/Training Program5%Mental Health Counselor - 3.9%Mental Health Counselor3.9%Pharmacist - 3.5%Pharmacist3.5%Clinical Social Worker - 3.1%Clinical Social Worker3.1%Rheumatology Physician - 0.1%Rheumatology Physician0.1%
Largest specialties in California (% of in-state 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 Rheumatology Physician. Verify directly:

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).

Bao Quynh Huynh, M.D. appears in the CMS NPPES registry as a Rheumatology Physician provider holding M.D. credentials at 2501 E. CHAPMAN AVE, Orange, CA, 92869, with a listed phone of (714) 628-3128. NPI 1538313648 was issued on 11/17/2008. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what Huynh 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 436 prescription claims written by this provider, covering 73 Medicare beneficiaries and totaling roughly $602K 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.

Rheumatology Physician is a mid-sized specialty nationwide, with 6,181 enrolled providers across 52 states and an average of 2,054 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

2501 E. CHAPMAN AVE
Orange, CA 92869

Provider Details

NPI 1538313648
Specialty Rheumatology Physician
Credentials M.D.
Gender Female
NPI Issued 11/17/2008

Hospital and facility affiliations

Facilities where Bao Quynh Huynh, M.D. bills Medicare from. Star ratings (1-5) are CMS Hospital Compare's "Hospital overall rating" - a composite of mortality, readmission, patient experience, safety, timely care, and efficient use of medical imaging measures. Source: CMS Care Compare.

Kern County Hospital Authority
Bakersfield, CA

Affiliations sourced from CMS Doctors and Clinicians National Downloadable File; hospital ratings from CMS Hospital General Information dataset (cross-referenced by facility name + state).

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 Bao Quynh Huynh, M.D.. Source: openpaymentsdata.cms.gov.

Total received

$96

Largest payer

Fresenius Kabi USA, LLC

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 Bao Quynh Huynh, M.D.. To verify Bao Quynh Huynh, 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.

Medicare Part D Prescribing Data

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

436
Total Claims
$602K
Total Drug Cost
73
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
581
Total Day Supply
16,795
Generic Drug Cost
$11K

Patient Demographics

Average Patient Age
62.3 years
Avg HCC Risk Score
1.72
Gender Split
77% female / 23% male
Age Distribution
<65: 36, 65-74: 31, 75-84: N/A, 85+: N/A

Top Prescribed Drugs (Medicare Part D)

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

What Bao Quynh Huynh, M.D. 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
Methotrexate
Methotrexate Sodium
102
Hydroxychloroquine Sulfate
61
Prednisone
53
Sulfasalazine
31
Azathioprine
30
Enbrel Sureclick
Etanercept
27
Benlysta
Belimumab
24
Allopurinol
23

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

Rheumatology Physician Overview

How Bao Quynh Huynh, M.D. fits within the Rheumatology Physician landscape nationally.

6,181
Rheumatology Physician Providers in US
52
States with Rheumatology Physician
2,054
Avg Claims per Provider

Bao Quynh Huynh, M.D.'s 436 claims are below the specialty average of 2,054.

Nearby Rheumatology Physician Providers in California

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

Compare Rheumatology 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 Rheumatology 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.

Frequently Asked Questions

What is Bao Quynh Huynh, M.D.'s specialty?
Bao Quynh Huynh, M.D. specializes in Rheumatology Physician and practices in Orange, California. Credentials: M.D..
How much does Bao Quynh Huynh, M.D. prescribe under Medicare Part D?
In 2023, Bao Quynh Huynh, M.D. wrote 436 Medicare Part D claims totaling $602K in drug costs for 73 beneficiaries.
Where is Bao Quynh Huynh, M.D. located?
Bao Quynh Huynh, M.D. is located at 2501 E. CHAPMAN AVE, Orange, CA, 92869. Phone: (714) 628-3128.
What is Bao Quynh Huynh, M.D.'s NPI number?
Bao Quynh Huynh, M.D.'s National Provider Identifier (NPI) is 1538313648, issued on 11/17/2008.
How many Rheumatology Physician providers are there in the US?
There are 6,181 Rheumatology Physician providers across 52 states in the US. The average Rheumatology Physician provider writes 2,054 Medicare Part D claims per year.
What drugs does Bao Quynh Huynh, M.D. prescribe most often?
Based on 2023 Medicare Part D data, Bao Quynh Huynh, M.D.'s most frequently prescribed drugs include Methotrexate, Hydroxychloroquine Sulfate, Prednisone. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Bao Quynh Huynh, M.D. accept Medicare?
Bao Quynh Huynh, M.D. appears in CMS Medicare data with 436 Part D claims and 73 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Bao Quynh Huynh, M.D.'s credentials?
Bao Quynh Huynh, M.D.'s NPI is 1538313648 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

Compiled from official public sources by the PlainDoctor editorial team.