Quick answers
- Does Demetrios S. Theodoropoulos accept Medicare assignment?
- Yes. Medicare's clinician data says Demetrios S. Theodoropoulos 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 Demetrios S. Theodoropoulos see?
- In 2024, CMS data shows 216 Original Medicare patients and 2,683 services for Demetrios S. Theodoropoulos. This counts Original Medicare only and measures volume, not quality.
- What is Demetrios S. Theodoropoulos's NPI number?
- 1326299488. 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 Demetrios S. Theodoropoulos, 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 | 216 |
|---|---|
| Services billed to Medicare | 2,683 |
| Different services or procedures | 25 |
| Participating Medicare provider | Yes |
| Average age of these patients | 73 |
Most frequent services
- Test for allergy using allergenic extract injected into skin (95024)2,025 services
- Measurement of antibody (ige) to allergic substance, crude allergen extract, each (86003)208 services
- Established patient office or other outpatient visit with low level od decision making, if using time, 20 minutes or more (99213)97 services
- Established patient office or other outpatient visit with moderate level of decision making, if using time, 30 minutes or more (99214)58 services
- Ige (immune system protein) level (82785)33 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 cholesterol62%
- High blood pressure57%
- Arthritis42%
- Asthma37%
- Anxiety24%
- Osteoporosis19%
Practice locations
Addresses where Demetrios S. Theodoropoulos is enrolled with Medicare (CMS data updated October 2, 2026).
- 2727 Midwest DrOnalaska, WI 54650
Group practices
Medicare enrollment lists Demetrios S. Theodoropoulos as a member of this group (CMS data updated October 2, 2026).
- Allergy Associates Holdings, Ltd5 clinicians in the group
Specialties
- Allergy/Immunologyprimary
Other allergist and immunologists in Wisconsin
Clinicians with the same Medicare primary specialty in Wisconsin — not a recommendation.
Other clinicians in Allergy Associates Holdings, Ltd
Medicare enrollment lists these clinicians in the same group practice — not a recommendation.
Clinician information
| Credential | MD |
|---|---|
| Graduation year | 1987 (39 years since medical school) |
| Gender (as listed) | Male |
| Medicare assignment | Accepts (Medicare-approved amount as full payment) |
| Telehealth | Offers telehealth services |
| NPI (National Provider Identifier) | 1326299488 |
| 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