Quick answers
- Does Marissa C. Niemeyer accept Medicare assignment?
- Yes. Medicare's clinician data says Marissa C. Niemeyer accepts Medicare assignment (the Medicare-approved amount as full payment for covered services), as of October 2, 2026. Ask the office to confirm before your visit.
- How many Medicare patients does Marissa C. Niemeyer see?
- In 2024, CMS data shows 28 Original Medicare patients and 33 services for Marissa C. Niemeyer. This counts Original Medicare only and measures volume, not quality.
- What is Marissa C. Niemeyer's NPI number?
- 1376019786. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Medicare activity in 2024
Official CMS public-use data for Marissa C. Niemeyer, data year 2024 (released May 21, 2026). It covers Original Medicare (fee-for-service) patients only, not Medicare Advantage or other insurance. It shows volume, not quality or outcomes. CMS hides any count of 10 or fewer patients.
| Original Medicare patients | 28 |
|---|---|
| Services billed to Medicare | 33 |
| Different services or procedures | 8 |
| Participating Medicare provider | Yes |
| Average age of these patients | 81 |
Most frequent services
- Critical care, first 30-74 minutes (99291)21 services
Chronic conditions among these patients
Share of this clinician’s Original Medicare patients with each condition, as published by CMS (it describes the patients, not the care given).
- High blood pressure75%
- High cholesterol75%
- Stroke or mini-stroke75%
- Arthritis57%
- Atrial fibrillation57%
- Ischemic heart disease54%
Hospitals where Marissa C. Niemeyer works
Medicare's Facility Affiliation Data lists Marissa C. Niemeyer at these hospitals (updated October 2, 2026). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians. Star rating and emergency services: Hospital General Information (CMS), data updated October 26, 2026.
- Inova Loudoun HospitalLeesburg, VA · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 490043
Practice locations
Addresses where Marissa C. Niemeyer is enrolled with Medicare (CMS data updated October 2, 2026).
- 44045 Rivderside PkwyLeesburg, VA 20176
Group practices
Medicare enrollment lists Marissa C. Niemeyer as a member of this group (CMS data updated October 2, 2026).
- Inova Health Care Services1,817 clinicians in the group
Specialties
- Physician Assistantprimary
Other physician assistants in Leesburg
Clinicians with the same Medicare primary specialty in Leesburg, VA — not a recommendation.
Other clinicians in Inova Health Care Services
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | PA |
|---|---|
| School | Duke University School Of Medicine |
| Graduation year | 2018 |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1376019786 |
| Corrections | Report an error or suggest an update → |
Most corrections must be made at the source: clinicians update their NPI Registry record (NPPES) and their Medicare enrollment (PECOS); this page follows the next data release.
Sources
- Facility Affiliation Data — Centers for Medicare & Medicaid Services (CMS), data updated October 2, 2026, retrieved October 29, 2026
- Hospital General Information — CMS, data updated October 26, 2026, retrieved November 13, 2026
- National Downloadable File (Doctors and Clinicians) — CMS, data updated October 2, 2026, retrieved October 29, 2026
- Medicare Physician & Other Practitioners - by Provider — CMS, data year 2024, released May 21, 2026; Medicare Physician & Other Practitioners - by Provider and Service
- NPI Registry — U.S. Department of Health and Human Services (NPPES), the clinician’s official record
- Medicare Care Compare — official Medicare tool to look up clinicians