2026 NPPES data Geriatric Medicine (Family Medicine) Physician NPI 1285620666 MD
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WILLIAM WARSHAL, MD

Geriatric Medicine (Family Medicine) Physician in LOS GATOS, California. CMS National Plan and Provider Enumeration System profile including specialty classification, practice address, and Medicare prescribing data when reported.

Federal data — no proprietary rating. PlainDoctor publishes the actual CMS NPPES and Medicare records — NPI registration, specialty, practice location, and prescribing data — without a composite score or editorial opinion on top. Every field traces to a federal source.
Prescribing volume
4K
Medicare Part D claims · 129 beneficiaries · Geriatric Medicine (Family Medicine) Physician avg: 5K

What the federal data shows

WILLIAM WARSHAL, MD filed 4,192 Medicare Part D claims in 2023 as a Geriatric Medicine (Family Medicine) Physician in LOS GATOS, California.

4K
Part D claims, 2023

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.

WILLIAM WARSHAL, MD's Medicare Part D volume vs every U.S. prescriber

Total Medicare Part D claims, 2023 — across all CMS prescribers nationally

4,192 Top 8% higher than 92% of 1,370,886 prescribers

0–200: 670,926 prescribers (49%). Below this entry. 200–400: 182,923 prescribers (13%). Below this entry. 400–600: 90,619 prescribers (7%). Below this entry. 600–800: 56,224 prescribers (4%). Below this entry. 800–1,000: 40,919 prescribers (3%). Below this entry. 1,000–1,200: 31,827 prescribers (2%). Below this entry. 1,200–1,400: 26,224 prescribers (2%). Below this entry. 1,400–1,600: 21,710 prescribers (2%). Below this entry. 1,600–1,800: 19,072 prescribers (1%). Below this entry. 1,800–2,000: 16,451 prescribers (1%). Below this entry. 2,000–2,200: 213,991 prescribers (16%). This entry sits in this band. This provider 0 2K+ every Part D prescriber (claims/yr), bucketed by value

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)

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 reported

NPI registry status

Active

Issued 09/21/2005

NPI 1285620666

Primary specialty

Geriatric Medicine (Family Medicine) Physician

Niche

1,779 US NPIs in this specialty

Medicare Part D claims

4,192 14% vs specialty avg

2023 prescription claims

Specialty avg: 4,854

Specialty distribution in California

How Geriatric Medicine (Family Medicine) Physician compares to other specialties among California providers

California providers

Geriatric Medicine (Family Medicine) Physician share within California

1. Geriatric Medicine (Family Medicine) Physician42%2. Internal medicine21%3. Family medicine17%4. Surgical12%5. Pediatric8%
Geriatric Medicine (Family Medicine) Physician share within California

Specialty board-certification context

Estimated specialty board-certified rate — Geriatric Medicine (Family Medicine) Physician (ABMS / AOA reference)

Quality data not reported
Est. board-certified rate
78%
Geriatric Medicine (Family Medicine) Physician ABMS/AOA estimate

Est. board-certified rate (Geriatric Medicine (Family Medicine) Physician) — ABMS / AOA estimate

0%100%78%
Est. board-certified rate (Geriatric Medicine (Family Medicine) Physician) — ABMS / AOA estimate

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).

WILLIAM WARSHAL, MD appears in the CMS NPPES registry as a Geriatric Medicine (Family Medicine) Physician provider holding MD credentials at 15251 NATIONAL AVE STE 104, LOS GATOS, CA, 95032, with a listed phone of (408) 605-8612. NPI 1285620666 was issued on 09/21/2005. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what WARSHAL most recently submitted to CMS rather than a vetted directory listing, which is why patients should always confirm the practice is still at this location before scheduling.

Medicare Part D records for calendar year 2023 show 4,192 prescription claims written by this provider, covering 129 Medicare beneficiaries and totaling roughly $175K in drug spend, with an opioid prescribing rate of 0.5%. These figures capture only Medicare Part D — commercial insurance, Medicaid, and cash-pay prescriptions are not included, and any drug-beneficiary cell under 11 is suppressed by CMS for patient privacy.

Geriatric Medicine (Family Medicine) Physician is a narrow specialty nationwide, with 1,779 enrolled providers across 52 states and an average of 4,854 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

15251 NATIONAL AVE STE 104
LOS GATOS, CA 95032

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.

Medicare Part D Prescribing Data

CMS Medicare Part D prescriber-level data for calendar year 2023.

4,192
Total Claims
$175K
Total Drug Cost
129
Medicare Beneficiaries

Prescribing Breakdown

30-Day Fills
4,230
Total Day Supply
76,210
Generic Drug Cost
$87K
Opioid Claims
20 (0.5% rate)
Antibiotic Claims
39

Patient Demographics

Average Patient Age
77.4 years
Avg HCC Risk Score
2.57
Gender Split
54% female / 46% male
Age Distribution
<65: 19, 65-74: 37, 75-84: 32, 85+: 41

Top Prescribed Drugs (Medicare Part D)

Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.

What WILLIAM WARSHAL, MD prescribes most

Top Medicare Part D drugs by claim count, 2023

claims
Source CMS Medicare Part D Prescriber Public Use File As of 2023
Drug Claims
Atorvastatin Calcium
274
Amlodipine Besylate
271
Levothyroxine Sodium
191
Metoprolol Tartrate
170
Gabapentin
163
Losartan Potassium
146
Tamsulosin Hcl
130
Furosemide
122
Eliquis
Apixaban
109
Metformin Hcl
101

* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.

Geriatric Medicine (Family Medicine) Physician Overview

How WILLIAM WARSHAL, MD fits within the Geriatric Medicine (Family Medicine) Physician landscape nationally.

1,779
Geriatric Medicine (Family Medicine) Physician Providers in US
52
States with Geriatric Medicine (Family Medicine) Physician
4,854
Avg Claims per Provider

WILLIAM WARSHAL, MD's 4,192 claims are below the specialty average of 4,854.

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.

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 2023, WILLIAM WARSHAL, MD wrote 4,192 Medicare Part D claims totaling $175K in drug costs for 129 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 opioids?
Yes, WILLIAM WARSHAL, MD had 20 opioid claims in 2023 with an opioid prescribing rate of 0.5%.
How many Geriatric Medicine (Family Medicine) Physician providers are there in the US?
There are 1,779 Geriatric Medicine (Family Medicine) Physician providers across 52 states in the US. The average Geriatric Medicine (Family Medicine) Physician provider writes 4,854 Medicare Part D claims per year.
What drugs does WILLIAM WARSHAL, MD prescribe most often?
Based on 2023 Medicare Part D data, WILLIAM WARSHAL, MD's most frequently prescribed drugs include Atorvastatin Calcium, Amlodipine Besylate, Levothyroxine Sodium. 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 4,192 Part D claims and 129 Medicare beneficiaries in 2023. 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

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