John Larson, SAC-IT
John Larson, SAC-IT is an Addiction (Substance Use Disorder) Counselor in Fond Du Lac, WI, registered under NPI 1619520251.
Getting there
The practice address on file is 430 E DIVISION ST, Fond Du Lac, WI 54935. 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 |
|---|---|---|
| 18138-130 | WI | Addiction (Substance Use Disorder)… primary |
This provider holds licence 18138-130 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 Addiction (Substance Use Disorder) covers
Definition to come... NUCC Health Care Provider Taxonomy, code 101YA0400X
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 | 1619520251 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Jul 23, 2019 |
| Last updated | Jul 23, 2019 |
| Status | Active |
| Sole proprietor | No |
| Credential | SAC-IT |
| Practice address |
430 E DIVISION ST Fond Du Lac, WI 54935 (920) 926-4172 |
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 | 1 | 9 | 5 | 2 | 0 | 2 | 5 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 6 | 2 | 9 | 1 | 2 | 0 | 2 | 1 |
Sum = 49 · next multiple of 10 = 50 · 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.