Quick answers
- Does Michael A. Grinney Ii accept Medicare assignment?
- Yes. Medicare's clinician data says Michael A. Grinney Ii 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 Michael A. Grinney Ii see?
- In 2024, CMS data shows 315 Original Medicare patients and 330 services for Michael A. Grinney Ii. This counts Original Medicare only and measures volume, not quality.
- What is Michael A. Grinney Ii's NPI number?
- 1972769198. 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 Michael A. Grinney Ii, 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 | 315 |
|---|---|
| Services billed to Medicare | 330 |
| Different services or procedures | 10 |
| Participating Medicare provider | Yes |
| Average age of these patients | 75 |
Most frequent services
- Emergency department visit with high level of medical decision making (99285)167 services
- Emergency department visit with moderate level of medical decision making (99284)74 services
- Critical care, first 30-74 minutes (99291)72 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%
- Arthritis62%
- Anxiety49%
- Ischemic heart disease47%
- Chronic kidney disease45%
Hospitals where Michael A. Grinney Ii works
Medicare's Facility Affiliation Data lists Michael A. Grinney Ii 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.
- Mayo ClinicJacksonville, FL · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 100151
Practice locations
Addresses where Michael A. Grinney Ii is enrolled with Medicare (CMS data updated October 2, 2026).
- 4500 San Pablo Rd SJacksonville, FL 32224 (904) 953‑2000
Group practices
Medicare enrollment lists Michael A. Grinney Ii as a member of this group (CMS data updated October 2, 2026).
- Mayo Clinic Jacksonville1,615 clinicians in the group
Specialties
- Emergency Medicineprimary
Other emergency medicine doctors in Jacksonville
Clinicians with the same Medicare primary specialty in Jacksonville, FL — not a recommendation.
Other clinicians in Mayo Clinic Jacksonville
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Wisconsin School Of Medicine |
| Graduation year | 2004 (22 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1972769198 |
| 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