Yolanda Olszewski, PSYD
Yolanda Olszewski, PSYD is a Mental Health Counselor in Warrenville, IL, registered under NPI 1861804775. 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 2S335 WILLIAMS RD, Warrenville, IL 60555. 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
NPPES does not list a state licence number for this record. That is not unusual — organizations and some provider types are not required to file one. Verify current licensure with the relevant state board before care.
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 Mental Health covers
Definition to come... NUCC Health Care Provider Taxonomy, code 101YM0800X
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 | 1861804775 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | May 27, 2014 |
| Last updated | Jan 6, 2017 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | PSYD |
| Practice address |
2S335 WILLIAMS RD Warrenville, IL 60555 (312) 560-1451 Fax (484) 297-0628 |
| Mailing address |
28379 DAVIS PKWY SUITE 801 Warrenville, IL 60555 |
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 | 8 | 6 | 1 | 8 | 0 | 4 | 7 | 7 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 8 | 3 | 1 | 7 | 0 | 8 | 7 | 5 |
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.