MARSHA ARMSTRONG, MD
Internal 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.
What stands out: MARSHA ARMSTRONG, MD filed 991 Medicare Part D claims in 2023 across LOS GATOS, California. Every figure on this page comes straight from federal CMS records, with no proprietary rating applied.
MARSHA ARMSTRONG, 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).
MARSHA ARMSTRONG, MD at a glance
Quality data not reportedPrimary specialty
Medicare Part D claims
Specialty distribution in California
How Internal Medicine Physician compares to other specialties among California providers
Internal Medicine Physician share within California
Internal Medicine Physician is one of the more visible NUCC categories in California
Each bar reflects the share of in-state providers whose primary NUCC taxonomy matches the specialty. Long tail of ~690 NUCC codes folded into "Other" to keep the comparison legible.
Specialty board-certification context
Estimated specialty board-certified rate — Internal Medicine Physician (ABMS / AOA reference)
- Est. board-certified rate
- 78%
- Internal Medicine Physician ABMS/AOA estimate
Est. board-certified rate (Internal Medicine Physician) — ABMS / AOA estimate
Verify credentials
- Verify via ABMS free public lookup
- Verify via AOA osteopathic boards
- Specialty volume Internal Medicine Physician US NPIs
Specialty board-certified rate — Internal Medicine Physician estimate
Board certification through an ABMS or AOA member board signals voluntary post-licensure examination plus Maintenance of Certification cycles. CMS does not publish a per-provider board-certification field; the figure shown is the specialty-level estimated rate from ABMS / AOA reference data.
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).
MARSHA ARMSTRONG, MD is a Internal Medicine Physician provider practicing in LOS GATOS, California, according to the CMS National Plan and Provider Enumeration System (NPPES). Credentials: MD. NPI: 1417041765. This profile includes practice location, specialty classification, and organizational affiliations from the CMS provider registry. Provider information is self-reported to CMS and updated monthly.
MARSHA ARMSTRONG, MD appears in the CMS NPPES registry as a Internal Medicine Physician provider holding MD credentials at 777 KNOWLES DR, LOS GATOS, CA, 95032, with a listed phone of (408) 370-3611. NPI 1417041765 was issued on 10/03/2006. Because NPPES data is self-reported by the provider and refreshed monthly, the address, phone, and specialty reflect what ARMSTRONG 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 991 prescription claims written by this provider, covering 58 Medicare beneficiaries and totaling roughly $47K in drug spend, split 10% brand-name and 90% generic by claim count, with an opioid prescribing rate of 1.7%. 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.
Internal Medicine Physician is a high-volume specialty nationwide, with 172,858 enrolled providers across 56 states and an average of 2,716 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 | 1417041765 |
|---|---|
| Specialty | Internal Medicine Physician |
| Credentials | MD |
| Gender | Female |
| NPI Issued | 10/03/2006 |
Verify this provider's license
PlainDoctor pulls this profile from the CMS NPPES public registry. Confirm MARSHA ARMSTRONG, MD's current license status, disciplinary history, and board certifications with the Medical Board of California in California before relying on this page for a clinical or care decision.
How we sourced this profile
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 MARSHA ARMSTRONG, MD. To verify MARSHA ARMSTRONG, MD's current license status, search the MBC public license lookup directly, or check the Federation of State Medical Boards (FSMB) verification service.
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
10% brand-name claims vs 90% generic, on 991 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.
Prescribing Breakdown
- 30-Day Fills
- 1,842
- Total Day Supply
- 53,341
- Brand vs Generic
- 10% brand / 90% generic
- Brand Drug Cost
- $28K
- Generic Drug Cost
- $19K
- Opioid Claims
- 17 (1.7% rate)
- Antibiotic Claims
- 53
Patient Demographics
- Average Patient Age
- 80.1 years
- Avg HCC Risk Score
- 0.99
- Gender Split
- 74% female / 26% male
Top Prescribed Drugs (Medicare Part D)
Top drugs by claim count for calendar year 2023. Based on Medicare Part D data only.
| Drug | Claims |
|---|---|
| Levothyroxine Sodium | 56 |
| Potassium Chloride | 53 |
| Allopurinol | 39 |
| Furosemide | 37 |
| Atorvastatin Calcium | 34 |
| Amitriptyline Hcl | 27 |
| Amlodipine Besylate | 27 |
| Gabapentin | 27 |
| Estradiol | 26 |
| Clopidogrel Clopidogrel Bisulfate | 25 |
* Counts below 11 are suppressed by CMS for patient privacy. Generic names shown where available from CMS Part D data.
Internal Medicine Physician Overview
How MARSHA ARMSTRONG, MD fits within the Internal Medicine Physician landscape nationally.
MARSHA ARMSTRONG, MD's 991 claims are below the specialty average of 2,716.
Nearby Internal Medicine Physician Providers in California
Other clinicians with the same primary specialty enrolled in California, drawn from the same CMS NPPES roster as ARMSTRONG.
Compare Internal Medicine Physician nationally: see state-by-state distribution →
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Frequently Asked Questions
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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