Quick answers
- Does Claire O. Williams accept Medicare assignment?
- Yes. Medicare's clinician data says Claire O. Williams 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 Claire O. Williams see?
- In 2024, CMS data shows 885 Original Medicare patients and 4,127 services for Claire O. Williams. This counts Original Medicare only and measures volume, not quality.
- What is Claire O. Williams's NPI number?
- 1629719737. 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 Claire O. Williams, 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 | 885 |
|---|---|
| Services billed to Medicare | 4,127 |
| Different services or procedures | 23 |
| Participating Medicare provider | Yes |
| Average age of these patients | 76 |
Most frequent services
- Destruction of precancer skin growth, 2-14 growths (17003)1,816 services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)725 services
- Destruction of precancer skin growth, 1 growth (17000)466 services
- Biopsy of related skin growth, first growth (11102)276 services
- Visit complexity inherent to evaluation and management associated with medical care services that serve as the continuing focal point for all needed health care services and/or with medical care services that are part of ongoing care related to a patient's (G2211)179 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 pressure69%
- Arthritis42%
- Diabetes23%
- Ischemic heart disease21%
- Chronic kidney disease20%
Hospitals where Claire O. Williams works
Medicare's Facility Affiliation Data lists Claire O. Williams 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.
- MercyOne North Iowa Medical CenterMason City, IA · Acute Care Hospital · Medicare rating: 2 of 5 stars · Emergency services: listed by Medicare · CCN 160064
Practice locations
Addresses where Claire O. Williams is enrolled with Medicare (CMS data updated October 2, 2026).
- 1000 4th St SWMason City, IA 50401
- 1421 4th St SW, Mercyone North Iowa Dermatology CareMason City, IA 50401 (641) 428‑2080
- 450 Laurel St, Suite ADes Moines, IA 50314 (515) 247‑8400
- 5300 NW 86th St, Suite 500Johnston, IA 50131 (515) 247‑8400
Group practices
Medicare enrollment lists Claire O. Williams as a member of these groups (CMS data updated October 2, 2026).
- North Iowa Mercy Clinics302 clinicians in the group
- Iowa Orthopaedic Center PC69 clinicians in the group
Specialties
- Physician Assistantprimary
Other physician assistants in Mason City
Clinicians with the same Medicare primary specialty in Mason City, IA — not a recommendation.
Other clinicians in North Iowa Mercy Clinics
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | PA |
|---|---|
| Graduation year | 2023 |
| Gender (as listed) | Female |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1629719737 |
| 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