Quick answers
- Does Thomas F. Marren accept Medicare assignment?
- Yes. Medicare's clinician data says Thomas F. Marren 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 Thomas F. Marren see?
- In 2024, CMS data shows 887 Original Medicare patients and 10,661 services for Thomas F. Marren. This counts Original Medicare only and measures volume, not quality.
- What is Thomas F. Marren's NPI number?
- 1952309833. 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 Thomas F. Marren, 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 | 887 |
|---|---|
| Services billed to Medicare | 10,661 |
| Different services or procedures | 83 |
| Participating Medicare provider | Yes |
| Average age of these patients | 72 |
Most frequent services
- Low osmolar contrast material, 300-399 mg/ml iodine concentration, per ml (Q9967)7,147 services
- Low osmolar contrast material, 200-299 mg/ml iodine concentration, per ml (Q9966)1,600 services
- Anticoagulant management of patient taking warfarin (93793)506 services
- X-ray of chest, 2 views (71046)217 services
- Screening mammography (77067)141 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 cholesterol67%
- High blood pressure64%
- Arthritis38%
- Ischemic heart disease25%
- Anxiety25%
- Diabetes22%
Hospitals where Thomas F. Marren works
Medicare's Facility Affiliation Data lists Thomas F. Marren 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.
- Aspirus Eagle River HospitalEagle River, WI · Critical Access Hospital · Emergency services: listed by Medicare · CCN 521300
- Aspirus Rhinelander HospitalRhinelander, WI · Acute Care Hospital · Medicare rating: 3 of 5 stars · Emergency services: listed by Medicare · CCN 520019
- Aspirus Tomahawk HospitalTomahawk, WI · Critical Access Hospital · Emergency services: listed by Medicare · CCN 521313
- Aspirus Wausau HospitalWausau, WI · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 520030
- Howard Young Medical CenterWoodruff, WI · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 520091
Practice locations
Addresses where Thomas F. Marren is enrolled with Medicare (CMS data updated October 2, 2026).
- 1630 Chippewa DrRhinelander, WI 54501 (715) 361‑5480
- 2251 N Shore DrRhinelander, WI 54501 (715) 361‑2000
- 2251 N Shore Dr, Suite 100Rhinelander, WI 54501
- 240 Maple StWoodruff, WI 54568 (715) 356‑8140
Group practices
Medicare enrollment lists Thomas F. Marren as a member of this group (CMS data updated October 2, 2026).
- Aspirus Rhinelander and Tomahawk Hospitals and Clinics, Inc.574 clinicians in the group
Specialties
- Family Practiceprimary
Other family doctors in Rhinelander
Clinicians with the same Medicare primary specialty in Rhinelander, WI — not a recommendation.
Other clinicians in Aspirus Rhinelander and Tomahawk Hospitals and Clinics, Inc.
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Loyola University Of Chicago, Stritch School Of Medicine |
| Graduation year | 2000 (26 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1952309833 |
| 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