NPI registry status
Active
2026 NPPES data Gastroenterology Physician NPI 1326228487 M.D.
Verify on CMS → Yen Quang, M.D.
Gastroenterology Physician in San Francisco, 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 16,601 in Gastroenterology 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
766
Medicare Part D claims · 293 beneficiaries · Gastroenterology Physician avg: 833
Generic prescribing
70%
generic claims · 30% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$168.85
2 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
Yen Quang, M.D. filed 766 Medicare Part D claims in 2023 as a Gastroenterology Physician in San Francisco, California, prescribing 70% generic.
- 766
- Part D claims, 2023
- 70%
- generic prescribing
- 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.
Yen Quang, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
766 Top 29% higher than 71% 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 certification likely (heuristic, not verified)
Yen Quang, 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 Yen Quang, M.D.?
Quality data not reportedPrimary specialty
Gastroenterology Physician
Medicare Part D claims
766 8% vs specialty avg
Specialty distribution in California
How Gastroenterology 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 Gastroenterology 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).
Yen Quang, M.D. appears in the CMS NPPES registry as a Gastroenterology Physician provider holding M.D. credentials at 1199 BUSH ST STE 560, San Francisco, CA, 94109, with a listed phone of (415) 885-8080. NPI 1326228487 was issued on 11/06/2007.
Medicare Part D records for calendar year 2023 show 766 prescription claims written by this provider, covering 293 Medicare beneficiaries and totaling roughly $213K in drug spend, split 30% brand-name and 70% generic by claim count.
Gastroenterology Physician is a mid-sized specialty nationwide, with 16,601 enrolled providers across 54 states and an average of 833 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 | 1326228487 |
|---|---|
| Specialty | Gastroenterology Physician |
| Credentials | M.D. |
| Gender | Female |
| NPI Issued | 11/06/2007 |
Hospital and facility affiliations
Facilities where Yen Quang, 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.
Quang Medical Practice Inc
San Francisco, 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 Yen Quang, M.D.. Source: openpaymentsdata.cms.gov.
Total received
$169
Largest payer
Janssen Pharmaceuticals, Inc
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 Yen Quang, M.D.. To verify Yen Quang, 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 · Above average
Yen Quang, M.D. - brand share 30.0%
Gastroenterology Physician average
30% brand-name claims vs 70% generic, on 766 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.
766
Total Claims
$213K
Total Drug Cost
293
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 1,405
- Total Day Supply
- 36,493
- Brand vs Generic
- 30% brand / 70% generic
- Brand Drug Cost
- $162K
- Generic Drug Cost
- $51K
- Antibiotic Claims
- 35
Patient Demographics
- Average Patient Age
- 74.4 years
- Avg HCC Risk Score
- 1.06
- Gender Split
- 68% female / 32% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Yen Quang, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2023
- Omeprazole
Omeprazole
120 claims
- Famotidine
Famotidine
112 claims
- Pantoprazole Sodium
Pantoprazole Sodium
57 claims
- Vemlidy
Vemlidy
53 claims
- Tenofovir Disoprox… 40
Tenofovir Disoproxil Fumarate
40 claims
- Linzess 38
Linzess
38 claims
- Dicyclomine Hcl 36
Dicyclomine Hcl
36 claims
- Creon 15
Creon
15 claims
| Drug | Claims |
|---|---|
| Omeprazole | 120 |
| Famotidine | 112 |
| Pantoprazole Sodium | 57 |
| Vemlidy Tenofovir Alafenamide | 53 |
| Tenofovir Disoproxil Fumarate | 40 |
| Linzess Linaclotide | 38 |
| Dicyclomine Hcl | 36 |
| Creon Lipase/Protease/Amylase | 15 |
| Sucralfate | 14 |
| Baraclude Entecavir | 12 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Gastroenterology Physician Overview
How Yen Quang, M.D. fits within the Gastroenterology Physician landscape nationally.
16,601
Gastroenterology Physician Providers in US
54
States with Gastroenterology Physician
833
Avg Claims per Provider
Yen Quang, M.D.'s 766 claims are below the specialty average of 833.
Nearby Gastroenterology Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Quang.
Dr. David Aarons
MD
Lodi, CA
Dr. Constante Abaya
MD
Oxnard, CA
Dr. Homan Abdollahzadeh
MD
Palm Springs, CA
Dr. John Abdulian
M.D.
Fresno, CA
Dr. Hussein Abidali
DO
Rancho Cucamonga, CA
Compare Gastroenterology 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 Gastroenterology 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.
Healthcare Guides
Learn more about finding, verifying, and understanding healthcare providers.
How to Find a Doctor
Step-by-step guide to choosing a provider
Verify Credentials
Check NPI, board certification & license status
Medical Specialties Explained
Who treats what and how specialties differ
Understanding Medicare Claims Data
What prescribing data reveals about a provider
In-Network vs Out-of-Network
How insurance networks affect your costs
Telehealth Guide
Virtual care options and coverage in 2026
Explore California
Frequently Asked Questions
What is Yen Quang, M.D.'s specialty? ▼
Yen Quang, M.D. specializes in Gastroenterology Physician and practices in San Francisco, California. Credentials: M.D..
How much does Yen Quang, M.D. prescribe under Medicare Part D? ▼
In 2023, Yen Quang, M.D. wrote 766 Medicare Part D claims totaling $213K in drug costs for 293 beneficiaries.
Where is Yen Quang, M.D. located? ▼
Yen Quang, M.D. is located at 1199 BUSH ST STE 560, San Francisco, CA, 94109. Phone: (415) 885-8080.
What is Yen Quang, M.D.'s NPI number? ▼
Yen Quang, M.D.'s National Provider Identifier (NPI) is 1326228487, issued on 11/06/2007.
Does Yen Quang, M.D. prescribe more brand-name or generic drugs? ▼
Yen Quang, M.D.'s prescribing is 30% brand-name and 70% generic drugs by claim count, with $162K in brand drug costs.
How many Gastroenterology Physician providers are there in the US? ▼
There are 16,601 Gastroenterology Physician providers across 54 states in the US. The average Gastroenterology Physician provider writes 833 Medicare Part D claims per year.
What drugs does Yen Quang, M.D. prescribe most often? ▼
Based on 2023 Medicare Part D data, Yen Quang, M.D.'s most frequently prescribed drugs include Omeprazole, Famotidine, Pantoprazole Sodium. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Yen Quang, M.D. accept Medicare? ▼
Yen Quang, M.D. appears in CMS Medicare data with 766 Part D claims and 293 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Yen Quang, M.D.'s credentials? ▼
Yen Quang, M.D.'s NPI is 1326228487 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.