Derek Fiedler, MS, DABR
Derek Fiedler, MS, DABR is a Radiological Physics Physician in Springfield, IL, registered under NPI 1679446447. NPPES records them as a sole proprietor, meaning the practice is not incorporated as a separate legal entity.
Getting there
The practice address on file is 701 N 1ST ST, Springfield, IL 62781. We have not yet mapped what surrounds this office — parking, transit, and nearby pharmacies are added as our data collection reaches each location.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| FMP02000228 | TX | Radiological Physics Physician primary |
This provider holds licence FMP02000228 issued in TX. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
This NPI does not appear in the PECOS Medicare enrolment file. Providers who do not bill Medicare — or who bill only through a group's enrolment — will not appear here. It is not a sign of any problem with the registration.
What Radiological Physics covers
A radiological physicist deals with the diagnostic and therapeutic applications of roentgen rays, gamma rays from sealed sources, ultrasonic radiation and radio-frequency radiation, as well as the equipment associated with their production and use, including radiation safety. NUCC Health Care Provider Taxonomy, code 2085R0205X
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1679446447 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Sep 26, 2025 |
| Last updated | Apr 7, 2026 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | MS, DABR |
| Practice address |
701 N 1ST ST Springfield, IL 62781 (847) 370-2194 |
| Mailing address |
6824 CORONADO AVE Dallas, TX 75214 |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 6 | 7 | 9 | 4 | 4 | 6 | 4 | 4 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 6 | 5 | 9 | 8 | 4 | 3 | 4 | 8 |
Sum = 73 · next multiple of 10 = 80 · check digit = 7 · actual last digit = 7
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.