Brenda Guillen, MD
Brenda Guillen, MD is an Obstetrics & Gynecology Physician in Chicago, IL, registered under NPI 1649066325. This provider registers 2 separate taxonomy codes, which usually means they practise across more than one recognised specialty.
Getting there
The practice address on file is 1620 W HARRISON ST, Chicago, IL 60612. 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 |
|---|---|---|
| 125.086852 | IL | Obstetrics & Gynecology Physician primary |
This provider holds licence 125.086852 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
- Order And Referring Only - Obstetrics/gynecology
- PAC ID
- 1254833213
- Enrollment ID
- I20250908003737
Medicare enrolment is recorded as approved under the provider type Order And Referring Only - Obstetrics/gynecology. Being enrolled means the provider can bill Medicare; it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
What Obstetrics & Gynecology covers
An obstetrician/gynecologist possesses special knowledge, skills and professional capability in the medical and surgical care of the female reproductive system and associated disorders. This physician serves as a consultant to other physicians and as a primary physician for women. NUCC Health Care Provider Taxonomy, code 207V00000X
All registered taxonomy codes
This provider registers 2 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 207V00000X | Obstetrics & Gynecology Physician | 125.086852 | IL | primary |
| 390200000X | Student in an Organized Health Care Education/Training Program | — | — |
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 | 1649066325 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Apr 17, 2025 |
| Last updated | Jun 22, 2025 |
| Status | Active |
| Sole proprietor | No |
| Credential | MD |
| Practice address |
1620 W HARRISON ST Chicago, IL 60612 (312) 942-5000 |
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 | 4 | 9 | 0 | 6 | 6 | 3 | 2 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 6 | 8 | 9 | 0 | 6 | 3 | 3 | 4 |
Sum = 65 · next multiple of 10 = 70 · check digit = 5 · actual last digit = 5
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.