Gad Marshall, MD
NPI 1639105513 · Neurology Physician · Boston, MA
Enrolled with Medicare as Practitioner - Neurology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Gad Marshall, MD is a Neurology Physician provider in Boston, MA (NPI 1639105513).
Provider details
- NPI number
- 1639105513
- Entity type
- Individual
- Primary specialty
- Neurology PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- A85728 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
20 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
141 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Prolonged Office Or Other Outpatient Evaluation and Management Service(s) Beyond the Maximum Required Time of the Primary Procedure Which Has Been Selected Using Total Time on the Date of the Primary Service; Each Additional 15 Minutes By the Physician OrG2212 | 67 | $32 |
| Established Patient Office Or Other Outpatient Visit With High Level of Medical Decision Making, If Using Time, 40 Minutes Or More99215 | 59 | $150 |
| Established Patient Office Or Other Outpatient Visit With Moderate Level of Decision Making, If Using Time, 30 Minutes Or More99214 | 15 | $102 |
Typical Medicare-allowed amounts for these services range $32–$150 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 5 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Donepezil Hcl | 73 | 21 |
| Trazodone Hcl | 36 | — |
| Escitalopram Oxalate | 33 | — |
| Citalopram Hydrobromidebrand: Citalopram Hbr | 12 | — |
| Methylphenidate Hcl | 11 | — |
Medicare Part D only. These counts cover prescriptions paid through Medicare Part D in 2024 — they do notinclude cash-pay, commercial-insurance, Medicaid, or Part B–administered drugs, and badly undercount high cash-pay categories (e.g. GLP-1 weight-loss, testosterone, and ED medications). Any drug with 10 or fewer claims is omitted by CMS, and beneficiary counts under 11 are suppressed — so a missing drug means , never zero. This is a factual claims summary, not an endorsement, not medical advice, and not a consumer report. Source: CMS Medicare Part D Prescribers — by Provider and Drug.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-06-23
- Last updated
- 2007-07-08
Frequently asked questions
- What is Gad Marshall's NPI number?
- Gad Marshall's National Provider Identifier (NPI) is 1639105513, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Gad Marshall's specialty?
- Gad Marshall is listed in the NPPES registry with a primary specialty of Neurology Physician (Allopathic & Osteopathic Physicians).
- Where is Gad Marshall located?
- Gad Marshall's practice location on file with NPPES is Bwh Memory Disorder Unit, Boston, MA 02115.
- What is Gad Marshall's phone number?
- The practice phone number listed in the NPPES registry for Gad Marshall is (617) 732-8085.
- Does Gad Marshall accept Medicare?
- Gad Marshall is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Gad Marshall's NPI active?
- Yes — Gad Marshall's NPI (1639105513) is active in the NPPES registry as of the last update on 2007-07-08.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.