NPI registry status
Active
2026 NPPES data Geriatric Medicine (Family Medicine) Physician NPI 1285620666 MD
Verify on CMS → William Warshal, MD
Geriatric Medicine (Family Medicine) Physician in Los Gatos, 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 1,792 in Geriatric Medicine (Family Medicine) 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
1K
Medicare Part D claims · 51 beneficiaries · Geriatric Medicine (Family Medicine) Physician avg: 5K
Generic prescribing
93%
generic claims · 7% 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
William Warshal, MD filed 1,399 Medicare Part D claims in 2024 as a Geriatric Medicine (Family Medicine) Physician in Los Gatos, California, prescribing 93% generic.
- 1K
- Part D claims, 2024
- 93%
- generic prescribing
- ≥79th
- 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 William Warshal, MD
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 1285620666), first enumerated 09/21/2005.
Source: CMS NPPES
- Reported
Medicare Part D participation
Filed 1,399 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
Practices in an ABMS-board-eligible specialty; board certification not confirmed in federal records.
- State context
State board disciplinary context
California statewide board action statistics are published annually — these figures describe aggregate state activity, not William Warshal, MD'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 1285620666 · Geriatric Medicine (Family Medicine) Physician
NPI-10 · ENUM-LEGACY · TAX-NARROW · RX-MID · BOOK-THIN · PHOTO-ENUM
- NPI-10 1285620666
- ENUM-LEGACY 2005
- TAX-NARROW 1,792
- RX-MID 1,399
- BOOK-THIN 250 in California
- PHOTO-ENUM Susan Pincus · 2005
William Warshal, MD's Medicare Part D volume vs every U.S. prescriber
Total Medicare Part D claims, 2024, across all CMS prescribers nationally
1,399 ≥ 79th percentile 79% 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-eligible specialty (heuristic, not verified)
William Warshal, MD 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 William Warshal, MD?
Quality data not reportedPrimary specialty
Geriatric Medicine (Family Medicine) Physician
Medicare Part D claims
1,399 72% vs specialty avg
Specialty distribution in California
How Geriatric Medicine (Family Medicine) 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 Geriatric Medicine (Family Medicine) 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 | 1285620666 |
|---|---|
| Specialty | Geriatric Medicine (Family Medicine) Physician |
| Credentials | MD |
| Gender | Male |
| NPI Issued | 09/21/2005 |
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 William Warshal, MD. To verify William Warshal, 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.
Brand vs generic prescribing mix · Generic-heavy
William Warshal, MD - brand share 7.0%
Geriatric Medicine (Family Medicine) Physician average
7% brand-name claims vs 93% generic, on 1,399 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.
1,399
Total Claims
$43K
Total Drug Cost
51
Medicare Beneficiaries
Prescribing Breakdown
- 30-Day Fills
- 1,402.1
- Total Day Supply
- 23,560
- Brand vs Generic
- 7% brand / 93% generic
- Brand Drug Cost
- $20K
- Generic Drug Cost
- $24K
Patient Demographics
- Average Patient Age
- 75.5 years
- Avg HCC Risk Score
- 2.49
- Gender Split
- 51% female / 49% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2024. Based on Medicare Part D data only.
What William Warshal, MD prescribes most
Top Medicare Part D drugs by claim count, 2024
- Amlodipine Besylate
Amlodipine Besylate
161 claims
- Metoprolol Tartrate
Metoprolol Tartrate
108 claims
- Atorvastatin Calcium
Atorvastatin Calcium
92 claims
- Losartan Potassium
Losartan Potassium
86 claims
- Levothyroxine Sodium
Levothyroxine Sodium
77 claims
- Gabapentin
Gabapentin
70 claims
- Tamsulosin Hcl 48
Tamsulosin Hcl
48 claims
- Famotidine 44
Famotidine
44 claims
| Drug | Claims |
|---|---|
| Amlodipine Besylate | 161 |
| Metoprolol Tartrate | 108 |
| Atorvastatin Calcium | 92 |
| Losartan Potassium | 86 |
| Levothyroxine Sodium | 77 |
| Gabapentin | 70 |
| Tamsulosin Hcl | 48 |
| Famotidine | 44 |
| Hydralazine Hcl | 40 |
| Carbamazepine | 36 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
More Geriatric Medicine (Family Medicine) Physician in CA →
All providers in California →
Compare specialties →
Geriatric Medicine (Family Medicine) Physician Overview
How William Warshal, MD fits within the Geriatric Medicine (Family Medicine) Physician landscape nationally.
1,792
Geriatric Medicine (Family Medicine) Physician Providers in US
52
States with Geriatric Medicine (Family Medicine) Physician
4,917
Avg Claims per Provider
William Warshal, MD's 1,399 claims are below the specialty average of 4,917.
Nationwide Geriatric Medicine (Family Medicine) Physician peers with similar MIPS or enrollment year
Two federal-record peer sets for Warshal, both outside California so the neighborhoods are not geographic containment.
Same NPPES enumeration year (2005)
Same-specialty clinicians who entered the NPI registry in the same calendar year, outside this state.
Nearby Geriatric Medicine (Family Medicine) Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as Warshal.
One of 250 Geriatric Medicine (Family Medicine) Physician providers enrolled in California, 5 are shown here.
Dr. Nagina Abdiani
DO
Orange, CA
Dr. Shivali Agarwal
M.D.
Fresno, CA
Dr. Kent Ahn
MD
Fontana, CA
Dr. Theresa Allison
M.D.
San Francisco, CA
Nancy Alvarez
NP
Simi Valley, CA
Compare Geriatric Medicine (Family Medicine) Physician nationally: see state-by-state distribution →
Frequently Asked Questions
What is William Warshal, MD's specialty? ▼
William Warshal, MD specializes in Geriatric Medicine (Family Medicine) Physician and practices in Los Gatos, California. Credentials: MD.
How much does William Warshal, MD prescribe under Medicare Part D? ▼
In 2024, William Warshal, MD wrote 1,399 Medicare Part D claims totaling $43K in drug costs for 51 beneficiaries.
Where is William Warshal, MD located? ▼
William Warshal, MD is located at 15251 NATIONAL AVE STE 104, Los Gatos, CA, 95032. Phone: (408) 605-8612.
What is William Warshal, MD's NPI number? ▼
William Warshal, MD's National Provider Identifier (NPI) is 1285620666, issued on 09/21/2005.
Does William Warshal, MD prescribe more brand-name or generic drugs? ▼
William Warshal, MD's prescribing is 7% brand-name and 93% generic drugs by claim count, with $20K in brand drug costs.
How many Geriatric Medicine (Family Medicine) Physician providers are there in the US? ▼
There are 1,792 Geriatric Medicine (Family Medicine) Physician providers across 52 states in the US. The average Geriatric Medicine (Family Medicine) Physician provider writes 4,917 Medicare Part D claims per year.
What drugs does William Warshal, MD prescribe most often? ▼
Based on 2024 Medicare Part D data, William Warshal, MD's most frequently prescribed drugs include Amlodipine Besylate, Metoprolol Tartrate, Atorvastatin Calcium. This reflects Medicare Part D prescriptions only and does not include commercial insurance or other payer types.
Does William Warshal, MD accept Medicare? ▼
William Warshal, MD appears in CMS Medicare data with 1,399 Part D claims and 51 Medicare beneficiaries in 2024. Contact the provider's office directly to confirm current Medicare enrollment and accepted plans.
How can I verify William Warshal, MD's credentials? ▼
William Warshal, MD's NPI is 1285620666 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 (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.