Quick answers
- Does James R. Siefer accept Medicare assignment?
- Yes. Medicare's clinician data says James R. Siefer 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 R. Siefer see?
- In 2024, CMS data shows 181 Original Medicare patients and 832 services for James R. Siefer. This counts Original Medicare only and measures volume, not quality.
- What is James R. Siefer's NPI number?
- 1508846627. 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 R. Siefer, 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 | 181 |
|---|---|
| Services billed to Medicare | 832 |
| Different services or procedures | 30 |
| Participating Medicare provider | Yes |
| Average age of these patients | 73 |
Most frequent services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)165 services
- Automated urinalysis test (81003)150 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)71 services
- New patient office or other outpatient visit with moderate level of medical decision making, if using time, 45 minutes or more (99204)64 services
- Ultrasound measurement of bladder capacity after voiding (51798)59 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 pressure75%
- High cholesterol75%
- Arthritis50%
- Ischemic heart disease31%
- Diabetes29%
- Chronic kidney disease25%
Practice locations
Addresses where James R. Siefer is enrolled with Medicare (CMS data updated October 2, 2026).
- 36493 N Gantzel Rd, Suite 100San Tan Valley, AZ 85140 (480) 394‑0200
Group practices
Medicare enrollment lists James R. Siefer as a member of this group (CMS data updated October 2, 2026).
- Arizona State Urological Institute LLC19 clinicians in the group
Specialties
- Urologyprimary
Other urologists in Arizona
Clinicians with the same Medicare primary specialty in Arizona — not a recommendation.
Other clinicians in Arizona State Urological Institute LLC
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | DO |
|---|---|
| Medical school | Midwestern University, Chicago College Of Osteopathic Med |
| Graduation year | 1973 (53 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| NPI (National Provider Identifier) | 1508846627 |
| 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
- 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