Quick answers
- Does James S. Iwakiri accept Medicare assignment?
- Yes. Medicare's clinician data says James S. Iwakiri 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 James S. Iwakiri see?
- In 2024, CMS data shows 667 Original Medicare patients and 16,888 services for James S. Iwakiri. This counts Original Medicare only and measures volume, not quality.
- What is James S. Iwakiri's NPI number?
- 1972689057. 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 James S. Iwakiri, 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 | 667 |
|---|---|
| Services billed to Medicare | 16,888 |
| Different services or procedures | 84 |
| Participating Medicare provider | Yes |
| Average age of these patients | 74 |
Most frequent services
- Injection, denosumab, 1 mg (J0897)3,180 services
- Injection, onabotulinumtoxina, 1 unit (J0585)2,000 services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)553 services
- Leuprolide acetate (for depot suspension), 7.5 mg (J9217)302 services
- Ultrasound measurement of bladder capacity after voiding (51798)142 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 pressure74%
- High cholesterol70%
- Cancer (breast, colorectal, lung, prostate, endometrial or leukemia/lymphoma)40%
- Arthritis36%
- Ischemic heart disease27%
- Diabetes26%
Hospitals where James S. Iwakiri works
Medicare's Facility Affiliation Data lists James S. Iwakiri 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 Stanley HospitalStanley, WI · Critical Access Hospital · Emergency services: listed by Medicare · CCN 521311
- Marshfield Medical CenterMarshfield, WI · Acute Care Hospital · Medicare rating: 1 of 5 stars · Emergency services: listed by Medicare · CCN 520037
- Marshfield Medical Center - Eau ClaireEau Claire, WI · Acute Care Hospital · Medicare rating: 3 of 5 stars · Emergency services: listed by Medicare · CCN 520210
- Marshfield Medical Center - LadysmithLadysmith, WI · Critical Access Hospital · Emergency services: listed by Medicare · CCN 521328
- Oakleaf Surgical HospitalAltoona, WI · Acute Care Hospital · Emergency services: not listed by Medicare · CCN 520196
Practice locations
Addresses where James S. Iwakiri is enrolled with Medicare (CMS data updated October 2, 2026). The first 5 of 6; the Medicare profile lists all.
- 1000 N Oak AveMarshfield, WI 54449 (715) 387‑5511
- 2310 Craig RdEau Claire, WI 54701 (715) 858‑8100
- 2655 County Hwy IChippewa Falls, WI 54729 (715) 726‑4200
- 2727 Plaza DrMarshfield, WI 54449
- 3217 Stein BlvdEau Claire, WI 54701 (715) 835‑6548
Group practices
Medicare enrollment lists James S. Iwakiri as a member of these groups (CMS data updated October 2, 2026).
- MCHS Hospitals Inc1,197 clinicians in the group
- Western Wisconsin Urology7 clinicians in the group
Specialties
- Urologyprimary
Other urologists in Marshfield
Clinicians with the same Medicare primary specialty in Marshfield, WI — not a recommendation.
Other clinicians in MCHS Hospitals Inc
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Medical school | Stanford University School Of Medicine |
| Graduation year | 1994 (32 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1972689057 |
| 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