Stephen Mattson, M.D.
Stephen Mattson, M.D. is a provider specialising in Military Health Care Provider in Oak Harbor, WA, registered under NPI 1164407474. 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 3475 N SARATOGA ST, Oak Harbor, WA 98278. 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 |
|---|---|---|
| MD00042954 | WA | Military Health Care Provider primary |
This provider holds licence MD00042954 issued in WA. 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 Military Health Care Provider covers
Active duty military health care providers not otherwise classified who need to be separately identified for operational, clinical, or administrative processes. NUCC Health Care Provider Taxonomy, code 171000000X
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 | 1164407474 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Dec 8, 2005 |
| Last updated | Oct 30, 2007 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | M.D. |
| Practice address |
3475 N SARATOGA ST Oak Harbor, WA 98278 (360) 257-9836 |
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 | 1 | 6 | 4 | 4 | 0 | 7 | 4 | 7 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 1 | 3 | 4 | 8 | 0 | 5 | 4 | 5 |
Sum = 56 · next multiple of 10 = 60 · check digit = 4 · actual last digit = 4
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.