NPI registry status
Active
2026 NPPES data Colon & Rectal Surgery Physician NPI 1225470354 M.D.
Verify on CMS → Roy Won, M.D.
Colon & Rectal Surgery Physician in Fullerton, 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 1,642 in Colon & Rectal Surgery 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
140
Medicare Part D claims · 68 beneficiaries · Colon & Rectal Surgery Physician avg: 210
Generic prescribing
92%
generic claims · 8% brand-name · higher generic rates reduce patient out-of-pocket costs
Source: CMS Medicare Part D Prescriber Public Use File, 2024
What the federal data shows
Roy Won, M.D. filed 140 Medicare Part D claims in 2024 as a Colon & Rectal Surgery Physician in Fullerton, California, prescribing 92% generic.
- 140
- Part D claims, 2024
- 92%
- generic prescribing
- Likely
- board-certified (heuristic)
- ≥34th
- pct by Part D claim volume (lower-bound band)
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.
Federal trust snapshot
What official records show about Roy Won, M.D.
Federal records show an active NPI with Medicare Part D prescribing activity — verifiable registry data, not a proprietary rating.
- Verified
NPI registry status
Active listing in the CMS National Provider Identifier Registry (NPI 1225470354), first enumerated 07/17/2013.
Source: CMS NPPES
- Reported
Medicare Part D participation
Filed 140 Medicare Part D prescription claims in the 2023 CMS public use file — indicates active Medicare prescribing participation.
Source: CMS Part D Prescriber PUF
- Reported
Board certification signal
Heuristic suggests board-certified status based on ABMS-eligible specialty taxonomy plus active CMS participation signals — not a direct ABMS verification.
- Reported
Hospital affiliations
2 CMS Care Compare hospital affiliations on record — practice footprint from the Doctors and Clinicians file.
Source: CMS Care Compare
- State context
State board disciplinary context
California statewide board action statistics are published annually — these figures describe aggregate state activity, not Roy Won, M.D.'s individual license status. Verify directly with the state medical board.
Source: MBC annual report 2023
- Not in federal data
Individual sanction lookup
PlainDoctor does not publish per-provider disciplinary determinations. Confirm current license and any individual actions through the state medical board or FSMB verification service.
Source: State medical board / FSMB
This trust snapshot summarizes only what appears in federal CMS/NPPES public records. It is not a composite score, star rating, patient review, or clinical recommendation. PlainDoctor never fabricates reviews or AggregateRating schema.
CMS NPPES provider registry desk
NPI 1225470354 · Colon & Rectal Surgery Physician
NPI-10 · ENUM-MID · TAX-NARROW · RX-LIGHT · BOOK-THIN · PHOTO-ENUM
- NPI-10 1225470354
- ENUM-MID 2013
- TAX-NARROW 1,642
- RX-LIGHT 140
- BOOK-THIN 142 in California
- PHOTO-ENUM David Rosen · 2013
Roy Won, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2024, across all CMS prescribers nationally
140 ≥ 34th percentile 34% of 1,416,883 prescribers are in lower value bands
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.
The percentile is a conservative 100-claim band: it counts only prescribers in lower claim-volume bands. Medicare Part D claim volume is activity context, not a quality measure or recommendation. See methodology § corpus placement.
Source CMS Medicare Part D Prescriber Public Use File · 2024
✓
Board certification likely (heuristic, not verified)
Roy Won, M.D. practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + 2 hospital affiliations - 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 Roy Won, M.D.?
Quality data not reportedPrimary specialty
Colon & Rectal Surgery Physician
Medicare Part D claims
140 33% vs specialty avg
Specialty distribution in California
How Colon & Rectal Surgery 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 Colon & Rectal Surgery 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).
Practice Address
Provider Details
| NPI | 1225470354 |
|---|---|
| Specialty | Colon & Rectal Surgery Physician |
| Credentials | M.D. |
| Gender | Male |
| NPI Issued | 07/17/2013 |
Hospital and facility affiliations
Facilities where Roy Won, 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.
Kaiser Foundation Health Plan OF The Mid Atlantic States, Inc
Largo, MD
Providence Medical Foundation
Fullerton, 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).
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 Roy Won, M.D.. To verify Roy Won, 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 · Generic-heavy
Roy Won, M.D. - brand share 8.0%
Colon & Rectal Surgery Physician average
8% brand-name claims vs 92% generic, on 140 2024 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 2024.
140
Total Claims
$2K
Total Drug Cost
68
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 141
- Total Day Supply
- 1,311
- Brand vs Generic
- 8% brand / 92% generic
- Brand Drug Cost
- $494
- Generic Drug Cost
- $2K
- Opioid Claims
- 27 (19.3% rate)
- Antibiotic Claims
- 45
Patient Demographics
- Average Patient Age
- 70.9 years
- Avg HCC Risk Score
- 1.53
- Gender Split
- 46% female / 54% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2024. Based on Medicare Part D data only.
What Roy Won, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2024
- Tramadol Hcl
Tramadol Hcl
23 claims
- Sod Sulf-Potass Su…
Sod Sulf-Potass Sulf-Mag Sulf
22 claims
- Metronidazole
Metronidazole
20 claims
- Neomycin Sulfate
Neomycin Sulfate
19 claims
- Hydrocortisone
Hydrocortisone
14 claims
| Drug | Claims |
|---|---|
| Tramadol Hcl | 23 |
| Sod Sulf-Potass Sulf-Mag Sulf Sodium, Potassium,mag Sulfates | 22 |
| Metronidazole | 20 |
| Neomycin Sulfate | 19 |
| Hydrocortisone | 14 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Colon & Rectal Surgery Physician Overview
How Roy Won, M.D. fits within the Colon & Rectal Surgery Physician landscape nationally.
1,642
Colon & Rectal Surgery Physician Providers in US
50
States with Colon & Rectal Surgery Physician
210
Avg Claims per Provider
Roy Won, M.D.'s 140 claims are below the specialty average of 210.
Nationwide Colon & Rectal Surgery Physician peers with similar MIPS or enrollment year
Two federal-record peer sets for Won, both outside California so the neighborhoods are not geographic containment.
Same NPPES enumeration year (2013)
Same-specialty clinicians who entered the NPI registry in the same calendar year, outside this state.
Nearby Colon & Rectal Surgery Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Won.
One of 142 Colon & Rectal Surgery Physician providers enrolled in California, 5 are shown here.
Dr. Kenneth Aaron
M.D.
Newport Beach, CA
Dr. Michael Abel
M.D.
San Francisco, CA
Dr. Piyush Aggarwal
MD
Walnut Creek, CA
Dr. Allison Aka
MD
Loma Linda, CA
Dr. Ahmed Alkoraishi
MD
Hayward, CA
Compare Colon & Rectal Surgery Physician nationally: see state-by-state distribution →
Frequently Asked Questions
What is Roy Won, M.D.'s specialty? ▼
Roy Won, M.D. specializes in Colon & Rectal Surgery Physician and practices in Fullerton, California. Credentials: M.D..
How much does Roy Won, M.D. prescribe under Medicare Part D? ▼
In 2024, Roy Won, M.D. wrote 140 Medicare Part D claims totaling $2K in drug costs for 68 beneficiaries.
Where is Roy Won, M.D. located? ▼
Roy Won, M.D. is located at 1950 SUNNY CREST DR STE 3500, Fullerton, CA, 92835. Phone: (714) 408-4249.
What is Roy Won, M.D.'s NPI number? ▼
Roy Won, M.D.'s National Provider Identifier (NPI) is 1225470354, issued on 07/17/2013.
Does Roy Won, M.D. prescribe more brand-name or generic drugs? ▼
Roy Won, M.D.'s prescribing is 8% brand-name and 92% generic drugs by claim count, with $494 in brand drug costs.
Does Roy Won, M.D. prescribe opioids? ▼
Yes, Roy Won, M.D. had 27 opioid claims in 2024 with an opioid prescribing rate of 19.3%.
How many Colon & Rectal Surgery Physician providers are there in the US? ▼
There are 1,642 Colon & Rectal Surgery Physician providers across 50 states in the US. The average Colon & Rectal Surgery Physician provider writes 210 Medicare Part D claims per year.
What drugs does Roy Won, M.D. prescribe most often? ▼
Based on 2024 Medicare Part D data, Roy Won, M.D.'s most frequently prescribed drugs include Tramadol Hcl, Sod Sulf-Potass Sulf-Mag Sulf, Metronidazole. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Roy Won, M.D. accept Medicare? ▼
Roy Won, M.D. appears in CMS Medicare data with 140 Part D claims and 68 Medicare beneficiaries in 2024. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Roy Won, M.D.'s credentials? ▼
Roy Won, M.D.'s NPI is 1225470354 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 (2024). 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 August 2026 (NPPES) / 2024 (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
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 August 2026.