Marianna Oppenheimer, MD, MSC
NPI 1538657762 · Emergency Medicine Physician · Walnut Creek, CA
Enrolled with Medicare as Practitioner - Emergency Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Marianna Oppenheimer, MD, MSC is a Emergency Medicine Physician provider in Walnut Creek, CA (NPI 1538657762).
Provider details
- NPI number
- 1538657762
- Entity type
- Individual
- Primary specialty
- Emergency Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD, MSC
- Sex
- Female
- Sole proprietor
- No
- License
- 35.140450 (OH)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Student, Health Care
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
8 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
4 documented practice locations
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 prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 1 distinct drug on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Ondansetronbrand: Ondansetron Odt | 15 | 15 |
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 no Part D record, 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
Additional practice locations (3)
- 759 Chestnut StSpringfield, MA 01199-1001Phone: (413) 794-0000
- 759 Chestnut StSpringfield, MA 01199-1001Phone: (413) 794-0000
- 395 W 12th Ave Rm 662Columbus, OH 43210Phone: (614) 293-8000Fax: (614) 293-4063
Registry dates
- Enumerated
- 2018-04-24
- Last updated
- 2024-08-12
- Certified
- 2024-08-12
Frequently asked questions
- What is Marianna Oppenheimer's NPI number?
- Marianna Oppenheimer's National Provider Identifier (NPI) is 1538657762, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Marianna Oppenheimer's specialty?
- Marianna Oppenheimer is listed in the NPPES registry with a primary specialty of Emergency Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Marianna Oppenheimer located?
- Marianna Oppenheimer's practice location on file with NPPES is 1425 S Main St, Walnut Creek, CA 94596-5318.
- What is Marianna Oppenheimer's phone number?
- The practice phone number listed in the NPPES registry for Marianna Oppenheimer is (925) 295-4000.
- Does Marianna Oppenheimer accept Medicare?
- Marianna Oppenheimer is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Marianna Oppenheimer's NPI active?
- Yes — Marianna Oppenheimer's NPI (1538657762) is active in the NPPES registry as of the last update on 2024-08-12.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.