Marc Zylstra, PH.D.
Marc Zylstra, PH.D. is a Group Psychotherapy Psychologist in Wauwatosa, WI, registered under NPI 1295847002. This provider registers 4 separate taxonomy codes, which usually means they practise across more than one recognised specialty.
Getting there
The practice address on file is 2525 N MAYFAIR RD SUITE 200, Wauwatosa, WI 53226. 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 |
|---|---|---|
| 1817-057 | WI | Group Psychotherapy Psychologist primary |
| 1817-057 | WI | Clinical Psychologist |
| 43715 | WI | Health Service Psychologist |
| 1817-057 | WI | Psychologist |
This provider holds licence 1817-057 issued in WI. 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 Group Psychotherapy covers
A psychologist who specializes in group psychology and group psychotherapy that is an evidenced-based specialty that prepares group leaders to identify and capitalize on developmental and healing possibilities embedded in the interpersonal/intrapersonal functioning of individual group members as well as collectively for the group. Emphasis is placed on the use of group dynamics to assist and treat individual group members. The specialty is applicable to all age groups, children, adolescents, adults and older adults, for a wide variety of conditions and concerns, and in numerous and diverse settings. NUCC Health Care Provider Taxonomy, code 103TP2701X
All registered taxonomy codes
This provider registers 4 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 103TP2701X | Group Psychotherapy Psychologist Group Psychotherapy | 1817-057 | WI | primary |
| 103TC0700X | Clinical Psychologist Clinical | 1817-057 | WI | |
| 103TH0100X | Health Service Psychologist Health Service | 43715 | WI | |
| 103T00000X | Psychologist | 1817-057 | WI |
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 | 1295847002 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Aug 31, 2006 |
| Last updated | Sep 11, 2025 |
| Status | Active |
| Sole proprietor | No |
| Credential | PH.D. |
| Practice address |
2525 N MAYFAIR RD SUITE 200 Wauwatosa, WI 53226 (414) 476-8183 Fax (414) 476-8465 |
| Other identifiers |
21280000
(WI) 39640900 (WI) |
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 | 2 | 9 | 5 | 8 | 4 | 7 | 0 | 0 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 2 | 9 | 5 | 7 | 4 | 5 | 0 | 0 |
Sum = 58 · next multiple of 10 = 60 · check digit = 2 · actual last digit = 2
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.