Quick answers
- Does Sean K. Shannahan accept Medicare assignment?
- Yes. Medicare's clinician data says Sean K. Shannahan 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 Sean K. Shannahan see?
- In 2024, CMS data shows 3,639 Original Medicare patients and 12,372 services for Sean K. Shannahan. This counts Original Medicare only and measures volume, not quality.
- What is Sean K. Shannahan's NPI number?
- 1831179571. 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 Sean K. Shannahan, 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 | 3,639 |
|---|---|
| Services billed to Medicare | 12,372 |
| Different services or procedures | 159 |
| Participating Medicare provider | Yes |
| Average age of these patients | 74 |
Most frequent services
- Low osmolar contrast material, 300-399 mg/ml iodine concentration, per ml (Q9967)6,937 services
- X-ray of chest, 1 view (71045)496 services
- X-ray of chest, 2 views (71046)474 services
- Screening mammography (77067)286 services
- Screening 3d breast mammography (77063)285 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 cholesterol71%
- High blood pressure70%
- Arthritis45%
- Diabetes28%
- Anxiety28%
- Ischemic heart disease26%
Hospitals where Sean K. Shannahan works
Medicare's Facility Affiliation Data lists Sean K. Shannahan 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.
- Lafayette Hospital and ClinicsDarlington, WI · Critical Access Hospital · Emergency services: listed by Medicare · CCN 521312
- Reedsburg Area Medical CenterReedsburg, WI · Critical Access Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 521351
- Sauk Prairie HospitalPrairie Du Sac, WI · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 520095
- SSM Health St Mary's Hospital - MadisonMadison, WI · Acute Care Hospital · Medicare rating: 4 of 5 stars · Emergency services: listed by Medicare · CCN 520083
- The Monroe ClinicMonroe, WI · Acute Care Hospital · Medicare rating: 5 of 5 stars · Emergency services: listed by Medicare · CCN 520028
Practice locations
Addresses where Sean K. Shannahan is enrolled with Medicare (CMS data updated October 2, 2026).
- 1211 Fish Hatchery RdMadison, WI 53715 (608) 252‑8000
- 700 S Park StMadison, WI 53715 (608) 251‑6100
Group practices
Medicare enrollment lists Sean K. Shannahan as a member of these groups (CMS data updated October 2, 2026).
- Dean Health Systems Inc1,159 clinicians in the group
- Madison Radiologists S C57 clinicians in the group
Specialties
- Diagnostic Radiologyprimary
Other radiologists in Madison
Clinicians with the same Medicare primary specialty in Madison, WI — not a recommendation.
Other clinicians in Dean Health Systems Inc
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Chicago College Of Medicine And Surgery |
| Graduation year | 1997 (29 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1831179571 |
| 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