Quick answers
- Does Marissa Gruenbaum accept Medicare assignment?
- Yes. Medicare's clinician data says Marissa Gruenbaum 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 Gruenbaum see?
- In 2024, CMS data shows 134 Original Medicare patients and 332 services for Marissa Gruenbaum. This counts Original Medicare only and measures volume, not quality.
- What is Marissa Gruenbaum's NPI number?
- 1811543861. 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 Gruenbaum, 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 | 134 |
|---|---|
| Services billed to Medicare | 332 |
| Different services or procedures | 42 |
| Participating Medicare provider | Yes |
| Average age of these patients | 78 |
Most frequent services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)47 services
- Injection, betamethasone acetate 3 mg and betamethasone sodium phosphate 3 mg (J0702)38 services
- Residence visit for established patient with low level of medical decision making, per day, if using time, at least 30 minutes (99348)28 services
- Residence visit for new patient with low level of medical decision making, per day, if using time, at least 30 minutes (99342)25 services
- Urinalysis, manual test (81002)23 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%
- Arthritis65%
- Ischemic heart disease47%
- Depression38%
- Atrial fibrillation35%
Practice locations
Addresses where Marissa Gruenbaum is enrolled with Medicare (CMS data updated October 2, 2026).
- 4604 Sawmill RdUpper Arlington, OH 43220 (614) 827‑8700
- 605 Crescent PlGahanna, OH 43230 (614) 545‑7900
Group practices
Medicare enrollment lists Marissa Gruenbaum as a member of this group (CMS data updated October 2, 2026).
- Orthopedic One, Inc.282 clinicians in the group
Specialties
- Physician Assistantprimary
Other physician assistants in Upper Arlington
Clinicians with the same Medicare primary specialty in Upper Arlington, OH — not a recommendation.
Other clinicians in Orthopedic One, Inc.
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Graduation year | 2018 |
|---|---|
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1811543861 |
| 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
- 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