NPI registry status
Active
2026 NPPES data Gastroenterology Physician NPI 1245215144 M.D.
Verify on CMS → Won-Seok Jo, M.D.
Gastroenterology Physician in San Bernardino, 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
2K
Medicare Part D claims · 949 beneficiaries · Gastroenterology Physician avg: 833
Generic prescribing
80%
generic claims · 20% brand-name · higher generic rates reduce patient out-of-pocket costs
Industry payments
$1.2K
65 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
Won-Seok Jo, M.D. filed 2,173 Medicare Part D claims in 2023 as a Gastroenterology Physician in San Bernardino, California, prescribing 80% generic.
- 2K
- Part D claims, 2023
- 80%
- generic prescribing
- $1.2K
- 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.
Won-Seok Jo, M.D.'s Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2023, across all CMS prescribers nationally
2,173 Top 15% higher than 85% 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)
Won-Seok Jo, 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 Won-Seok Jo, M.D.?
Quality data not reportedPrimary specialty
Gastroenterology Physician
Medicare Part D claims
2,173 161% 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).
Won-Seok Jo, M.D. appears in the CMS NPPES registry as a Gastroenterology Physician provider holding M.D. credentials at 424 E VANDERBILT WAY STE B, San Bernardino, CA, 92408, with a listed phone of (909) 796-0363. NPI 1245215144 was issued on 12/13/2005.
Medicare Part D records for calendar year 2023 show 2,173 prescription claims written by this provider, covering 949 Medicare beneficiaries and totaling roughly $602K in drug spend, split 20% brand-name and 80% 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 | 1245215144 |
|---|---|
| Specialty | Gastroenterology Physician |
| Credentials | M.D. |
| Gender | Male |
| NPI Issued | 12/13/2005 |
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 Won-Seok Jo, M.D.. Source: openpaymentsdata.cms.gov.
Total received
$1.2K
Largest payer
Gilead Sciences, 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 Won-Seok Jo, M.D.. To verify Won-Seok Jo, 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
Won-Seok Jo, M.D. - brand share 20.0%
Gastroenterology Physician average
20% brand-name claims vs 80% generic, on 2,173 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.
2,173
Total Claims
$602K
Total Drug Cost
949
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 2,759
- Total Day Supply
- 56,467
- Brand vs Generic
- 20% brand / 80% generic
- Brand Drug Cost
- $551K
- Generic Drug Cost
- $51K
- Antibiotic Claims
- 100
Patient Demographics
- Average Patient Age
- 69.4 years
- Avg HCC Risk Score
- 1.72
- Gender Split
- 56% female / 44% male
- Age Distribution
- <65: 140, 65-74: 607, 75-84: 175, 85+: 27
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Won-Seok Jo, M.D. prescribes most
Top Medicare Part D drugs by claim count, 2023
- Omeprazole
Omeprazole
249 claims
- Famotidine
Famotidine
231 claims
- Linzess
Linzess
110 claims
- Dicyclomine Hcl 67
Dicyclomine Hcl
67 claims
- Sucralfate 65
Sucralfate
65 claims
- Cholestyramine 52
Cholestyramine
52 claims
- Pantoprazole Sodium 44
Pantoprazole Sodium
44 claims
- Propranolol Hcl 40
Propranolol Hcl
40 claims
| Drug | Claims |
|---|---|
| Omeprazole | 249 |
| Famotidine | 231 |
| Linzess Linaclotide | 110 |
| Dicyclomine Hcl | 67 |
| Sucralfate | 65 |
| Cholestyramine Cholestyramine (With Sugar) | 52 |
| Pantoprazole Sodium | 44 |
| Propranolol Hcl | 40 |
| Peg 3350-Electrolyte Sodium Chloride/Nahco3/Kcl/Peg | 38 |
| Ondansetron Hcl | 35 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Gastroenterology Physician Overview
How Won-Seok Jo, 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
Won-Seok Jo, M.D.'s 2,173 claims are above 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 Jo.
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.
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Frequently Asked Questions
What is Won-Seok Jo, M.D.'s specialty? ▼
Won-Seok Jo, M.D. specializes in Gastroenterology Physician and practices in San Bernardino, California. Credentials: M.D..
How much does Won-Seok Jo, M.D. prescribe under Medicare Part D? ▼
In 2023, Won-Seok Jo, M.D. wrote 2,173 Medicare Part D claims totaling $602K in drug costs for 949 beneficiaries.
Where is Won-Seok Jo, M.D. located? ▼
Won-Seok Jo, M.D. is located at 424 E VANDERBILT WAY STE B, San Bernardino, CA, 92408. Phone: (909) 796-0363.
What is Won-Seok Jo, M.D.'s NPI number? ▼
Won-Seok Jo, M.D.'s National Provider Identifier (NPI) is 1245215144, issued on 12/13/2005.
Does Won-Seok Jo, M.D. prescribe more brand-name or generic drugs? ▼
Won-Seok Jo, M.D.'s prescribing is 20% brand-name and 80% generic drugs by claim count, with $551K 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 Won-Seok Jo, M.D. prescribe most often? ▼
Based on 2023 Medicare Part D data, Won-Seok Jo, M.D.'s most frequently prescribed drugs include Omeprazole, Famotidine, Linzess. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Won-Seok Jo, M.D. accept Medicare? ▼
Won-Seok Jo, M.D. appears in CMS Medicare data with 2,173 Part D claims and 949 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Won-Seok Jo, M.D.'s credentials? ▼
Won-Seok Jo, M.D.'s NPI is 1245215144 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.