NPI registry status
Active
2026 NPPES data MOHS-Micrographic Surgery Physician NPI 1023460243 MD
Verify on CMS → Ji Won Ahn, MD
MOHS-Micrographic Surgery Physician in Walnut Creek, 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 1,102 in MOHS-Micrographic 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
390
Medicare Part D claims · 214 beneficiaries · MOHS-Micrographic Surgery Physician avg: 607
MIPS score
77.5/100
▼ 6 pts below national avg 83.1 · Above neutral
Compiled from official public sources by the PlainDoctor editorial team.
What the federal data shows
Ji Won Ahn, MD reported a CMS MIPS final score of 77.5/100 - below the 83.1 national average - and filed 390 Medicare Part D claims in 2023.
- 77.5/100
- MIPS score · -6 vs avg
- 390
- 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.
Ji Won Ahn, MD's MIPS score vs every scored U.S. clinician
CMS Merit-based Incentive Payment System (MIPS) final score, 2023, the federal quality measure
78 24th percentile higher than 24% of 477,587 scored providers
Each bar is a band; taller bars hold more scored providers. 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 Merit-based Incentive Payment System (MIPS) · 2023
Where Ji Won Ahn, MD sits
This provider among mohs-micrographic surgery physician peers
Across the 705 mohs-micrographic surgery physician providers who report both Medicare Part D prescribing and a MIPS quality score, Ji Won Ahn, MD writes more Part D claims than 40% of them and scores higher on MIPS quality than 34% - placing this provider in the lower-volume, lower-quality quadrant. Volume reflects patient-panel size and specialty, not quality; the two axes are independent.
Part D claim volume vs MIPS quality, by specialty percentile
Each dot is one mohs-micrographic surgery physician peer from a representative sample of 60; the gold marker is Ji Won Ahn, MD. Source: CMS Medicare Part D Prescriber data and the CMS Merit-based Incentive Payment System, 2023.
✓
Board certification likely (heuristic, not verified)
Ji Won Ahn, MD practices in an ABMS-board-eligible specialty and shows active CMS Medicare participation + MIPS quality reporting + 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 Ji Won Ahn, MD?
Below national averagePrimary specialty
MOHS-Micrographic Surgery Physician
Medicare Part D claims
390 36% vs specialty avg
MIPS final score
77.5/100 5.6 pts vs avg
Specialty distribution in California
How MOHS-Micrographic Surgery Physician compares to other specialties among California providers
Medicare quality performance, MIPS
Ji Won Ahn, MD's 2023 MIPS final score plotted against the MOHS-Micrographic Surgery Physician national average
- MIPS Final Score
- 77.5/100
- vs 83.1 national avg · 2023 performance year
MIPS final score (MOHS-Micrographic Surgery Physician) - 77.5/100 vs national avg 83.1
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).
Ji Won Ahn, MD appears in the CMS NPPES registry as a MOHS-Micrographic Surgery Physician provider holding MD credentials at 320 LENNON LN DEPT OF, Walnut Creek, CA, 94598, with a listed phone of (925) 817-5678. NPI 1023460243 was issued on 07/12/2016.
Medicare Part D records for calendar year 2023 show 390 prescription claims written by this provider, covering 214 Medicare beneficiaries and totaling roughly $21K in drug spend, with an opioid prescribing rate of 5.4%. On the CMS Merit-based Incentive Payment System, this provider earned a Final Score of 77.5/100 for the 2023 performance year (Quality 68.6, Cost 56.4), compared with the national average of 83.1.
MOHS-Micrographic Surgery Physician is a narrow specialty nationwide, with 1,102 enrolled providers across 52 states and an average of 607 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 | 1023460243 |
|---|---|
| Specialty | MOHS-Micrographic Surgery Physician |
| Credentials | MD |
| Gender | Female |
| NPI Issued | 07/12/2016 |
CMS Quality Score (MIPS)
Merit-based Incentive Payment System (MIPS) scores from CMS, 2023 performance year.
77.5068
Final Score
Avg: 83.1
68.6144
Quality
56.4081
Cost
100
Promoting Interoperability
Reporting: Group practice
Hospital and facility affiliations
Facilities where Ji Won Ahn, MD 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.
Permanente Medical Group Inc
Walnut Creek, 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 Ji Won Ahn, MD. To verify Ji Won Ahn, MD'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.
390
Total Claims
$21K
Total Drug Cost
214
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 400
- Total Day Supply
- 5,310
- Generic Drug Cost
- $5K
- Opioid Claims
- 21 (5.4% rate)
- Antibiotic Claims
- 203
Patient Demographics
- Average Patient Age
- 75.8 years
- Avg HCC Risk Score
- 1.31
- Gender Split
- 40% female / 60% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
What Ji Won Ahn, MD prescribes most
Top Medicare Part D drugs by claim count, 2023
- Cefadroxil
Cefadroxil
141 claims
- Mupirocin
Mupirocin
95 claims
- Doxycycline Hyclate 52
Doxycycline Hyclate
52 claims
- Fluorouracil 23
Fluorouracil
23 claims
- Tramadol Hcl 19
Tramadol Hcl
19 claims
| Drug | Claims |
|---|---|
| Cefadroxil | 141 |
| Mupirocin | 95 |
| Doxycycline Hyclate | 52 |
| Fluorouracil | 23 |
| Tramadol Hcl | 19 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
More MOHS-Micrographic Surgery Physician in CA →
All providers in California →
Compare specialties →
MOHS-Micrographic Surgery Physician Overview
How Ji Won Ahn, MD fits within the MOHS-Micrographic Surgery Physician landscape nationally.
1,102
MOHS-Micrographic Surgery Physician Providers in US
52
States with MOHS-Micrographic Surgery Physician
607
Avg Claims per Provider
Ji Won Ahn, MD's 390 claims are below the specialty average of 607.
Nearby MOHS-Micrographic Surgery Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Ahn.
Dr. Sam Abaza
M.D.
Diamond Bar, CA
Dr. Payam Abrishami
MD
Agoura Hills, CA
Dr. Vince Afsahi
M.D.
Tustin, CA
Dr. Kristen Aguirre
MD
Oceanside, CA
Dr. Joseph Aleshaki
DO
Santee, CA
Compare MOHS-Micrographic Surgery 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 MOHS-Micrographic Surgery 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 Ji Won Ahn, MD's specialty? ▼
Ji Won Ahn, MD specializes in MOHS-Micrographic Surgery Physician and practices in Walnut Creek, California. Credentials: MD.
How much does Ji Won Ahn, MD prescribe under Medicare Part D? ▼
In 2023, Ji Won Ahn, MD wrote 390 Medicare Part D claims totaling $21K in drug costs for 214 beneficiaries.
What is Ji Won Ahn, MD's Medicare quality score? ▼
Ji Won Ahn, MD has a CMS MIPS Final Score of 77.5/100 (Quality: 68.6, Cost: 56.4). The national average MIPS Final Score is 83.1. Source: CMS Merit-based Incentive Payment System (MIPS) 2023.
Where is Ji Won Ahn, MD located? ▼
Ji Won Ahn, MD is located at 320 LENNON LN DEPT OF, Walnut Creek, CA, 94598. Phone: (925) 817-5678.
What is Ji Won Ahn, MD's NPI number? ▼
Ji Won Ahn, MD's National Provider Identifier (NPI) is 1023460243, issued on 07/12/2016.
Does Ji Won Ahn, MD prescribe opioids? ▼
Yes, Ji Won Ahn, MD had 21 opioid claims in 2023 with an opioid prescribing rate of 5.4%.
How many MOHS-Micrographic Surgery Physician providers are there in the US? ▼
There are 1,102 MOHS-Micrographic Surgery Physician providers across 52 states in the US. The average MOHS-Micrographic Surgery Physician provider writes 607 Medicare Part D claims per year.
What drugs does Ji Won Ahn, MD prescribe most often? ▼
Based on 2023 Medicare Part D data, Ji Won Ahn, MD's most frequently prescribed drugs include Cefadroxil, Mupirocin, Doxycycline Hyclate. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does Ji Won Ahn, MD accept Medicare? ▼
Ji Won Ahn, MD appears in CMS Medicare data with 390 Part D claims and 214 Medicare beneficiaries in 2023. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify Ji Won Ahn, MD's credentials? ▼
Ji Won Ahn, MD's NPI is 1023460243 with credentials MD. 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.
- Quality Performance
- CMS Merit-based Incentive Payment System (MIPS) - 2023 performance year.
- 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.