Leonard Donk, PHD
Leonard Donk, PHD is a Clinical Child & Adolescent Psychologist in Cupertino, CA, registered under NPI 1942420591. This provider registers 8 separate taxonomy codes, which usually means they practise across more than one recognised specialty. 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 20111 STEVENS CREEK BLVD SUITE 250, Cupertino, CA 95014. 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 |
|---|---|---|
| 9064 | CA | Clinical Child & Adolescent Psychologist primary |
| 9064 | CA | Psychologist |
| 9064 | CA | Cognitive & Behavioral Psychologist |
| 9064 | CA | Clinical Psychologist |
| 9064 | CA | Counseling Psychologist |
| 9064 | CA | Forensic Psychologist |
| 9064 | CA | Health Psychologist |
| 9064 | CA | Psychoanalysis Psychologist |
This provider holds licence 9064 issued in CA. 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 Clinical Child & Adolescent covers
A psychologist who develops and applies scientific knowledge to the delivery of psychological services to infants, toddlers, children and adolescents within their social context. Of particular importance to the specialty of clinical child psychology is an understanding of the basic psychological needs of children and adolescents, and how the family and other social contexts influence the socio-emotional adjustment, cognitive development, behavioral adaptation and health status of children and adolescents. NUCC Health Care Provider Taxonomy, code 103TC2200X
All registered taxonomy codes
This provider registers 8 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 103TC2200X | Clinical Child & Adolescent Psychologist Clinical Child & Adolescent | 9064 | CA | primary |
| 103T00000X | Psychologist | 9064 | CA | |
| 103TB0200X | Cognitive & Behavioral Psychologist Cognitive & Behavioral | 9064 | CA | |
| 103TC0700X | Clinical Psychologist Clinical | 9064 | CA | |
| 103TC1900X | Counseling Psychologist Counseling | 9064 | CA | |
| 103TF0200X | Forensic Psychologist Forensic | 9064 | CA | |
| 103TH0004X | Health Psychologist Health | 9064 | CA | |
| 103TP0814X | Psychoanalysis Psychologist Psychoanalysis | 9064 | CA |
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 | 1942420591 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Apr 26, 2007 |
| Last updated | Sep 11, 2025 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | PHD |
| Practice address |
20111 STEVENS CREEK BLVD SUITE 250 Cupertino, CA 95014 (408) 366-9910 Fax (408) 366-9915 |
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 | 9 | 4 | 2 | 4 | 2 | 0 | 5 | 9 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 9 | 8 | 2 | 8 | 2 | 0 | 5 | 9 |
Sum = 69 · next multiple of 10 = 70 · check digit = 1 · actual last digit = 1
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.