Quick answers
- Which hospitals does Ryan M. Holthaus work at?
- Medicare's official clinician data lists Ryan M. Holthaus at 5 hospitals: Allen Hospital, Hancock County Health System, Kossuth Regional Health Center, MercyOne North Iowa Medical Center and Mitchell County Regional Health. This is where the clinician works or has privileges; call the hospital to confirm.
- Where does Ryan M. Holthaus see patients?
- Medicare's clinician data lists 3 practice locations, including Mason City, IA and Waterloo, IA. Call before your visit to confirm the address.
- What is Ryan M. Holthaus's specialty?
- Medicare lists Diagnostic Radiology as the primary specialty.
- Does Ryan M. Holthaus accept Medicare assignment?
- Medicare's clinician data says Ryan M. Holthaus may accept Medicare assignment (as of 2026-10-02). Ask the office whether they accept it for your visit.
- What is the phone number for Ryan M. Holthaus?
- (641) 424-0102, as listed in official Medicare / NPI Registry data.
- What is Ryan M. Holthaus's NPI number?
- 1609822873. The NPI (National Provider Identifier) is the clinician's permanent federal ID; you can look it up in the official NPI Registry.
Hospitals where Ryan M. Holthaus works
Medicare's Facility Affiliation Data lists Ryan M. Holthaus at these hospitals (updated 2026-10-02). Each hospital page shows its address, phone, emergency services, Medicare rating and all its clinicians.
- Allen HospitalWaterloo, IA · Acute Care Hospital · CCN 160110
- Hancock County Health SystemBritt, IA · Critical Access Hospital · CCN 161307
- Kossuth Regional Health CenterAlgona, IA · Critical Access Hospital · CCN 161353
- MercyOne North Iowa Medical CenterMason City, IA · Acute Care Hospital · CCN 160064
- Mitchell County Regional HealthOsage, IA · Critical Access Hospital · CCN 161323
Practice locations
Addresses where Ryan M. Holthaus is enrolled with Medicare (CMS data updated 2026-10-02).
- 1416 6th St SWMason City, IA 50401 (641) 424‑0102
- 1825 Logan AveWaterloo, IA 50703
- 225 Pebble Creek DrMason City, IA 50401 (319) 235‑3697
Group practices
Medicare enrollment lists Ryan M. Holthaus as a member of these groups (CMS data updated 2026-10-02).
- Allen Memorial Hospital Corporation157 clinicians in the group
- Radiologists of North Iowa PC13 clinicians in the group
Specialties
- Diagnostic Radiologyprimary
Other radiologists in Mason City
Clinicians with the same Medicare primary specialty in Mason City, IA — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | University Of Iowa, Rj & L Carver College Of Medicine |
| Graduation year | 2001 |
| Gender (as listed) | Male |
| Medicare assignment | May accept for some services |
| NPI (National Provider Identifier) | 1609822873 |
| 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 2026-10-02, retrieved 2026-10-29
- National Downloadable File (Doctors and Clinicians) — CMS, data updated 2026-10-02, retrieved 2026-10-29
- 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