James Ruffer, M.D.
James Ruffer, M.D. is a Radiation Oncology Physician in Chicago, IL, registered under NPI 1679564629.
Getting there
The practice address on file is 900 W NELSON ST, Chicago, IL 60657. 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 |
|---|---|---|
| 036099331 | IL | Radiation Oncology Physician primary |
This provider holds licence 036099331 issued in IL. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
- Status
- Approved
- Provider type
- Practitioner - Radiation Oncology
- PAC ID
- 2769469048
Medicare enrolment is recorded as approved under the provider type Practitioner - Radiation Oncology. This means the provider is enrolled to bill Medicare, though it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
What Radiation Oncology covers
A radiologist who deals with the therapeutic applications of radiant energy and its modifiers and the study and management of disease, especially malignant tumors. NUCC Health Care Provider Taxonomy, code 2085R0001X
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 | 1679564629 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Oct 31, 2005 |
| Last updated | Dec 27, 2021 |
| Status | Active |
| Sole proprietor | No |
| Credential | M.D. |
| Practice address |
900 W NELSON ST Chicago, IL 60657 (773) 296-7076 |
| Mailing address |
700 COMMERCE DR SUITE 500 Oak Brook, IL 60523 |
| Other identifiers |
920005580
· RAILROAD MEDICARE (IL) 778401 · MEDICARE PROVIDER NUMBER (IL) 036099331 (IL) 558620 · MEDICARE PROVIDER NUMBER (IL) 920005272 · RAILROAD MEDICARE (IL) |
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 | 5 | 6 | 4 | 6 | 2 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 6 | 5 | 9 | 1 | 6 | 8 | 6 | 4 |
Sum = 71 · next multiple of 10 = 80 · check digit = 9 · actual last digit = 9
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.