Isaac Fonken, M.D.
Isaac Fonken, M.D. is a Family Medicine Physician in Tacoma, WA, registered under NPI 1538665542. 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 1112 6TH AVE 3-TFM, Tacoma, WA 98405. 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 |
|---|---|---|
| MD.MD.61669853 | WA | Family Medicine Physician primary |
| 101180 | MT | Family Medicine Physician |
Licences are recorded in 2 states: WA, MT. Providers licensed in several states often practise near a state border or deliver telehealth across state lines.
- Status
- Approved
- Provider type
- Practitioner - Family Practice
- PAC ID
- 7810251113
Enrolled in Medicare 2 times, across 2 states:
| State | Enrollment ID | Provider type |
|---|---|---|
| Montana | I20210901003846 | Practitioner - Family Practice |
| Washington | I20250730003885 | Practitioner - Family Practice |
Medicare enrolment is recorded as approved under the provider type Practitioner - Family Practice. There are 2 separate enrolment records across 2 states (MT, WA). Multiple enrolments usually mean the provider bills Medicare from more than one practice location, or has kept an earlier enrolment after moving. Each record carries its own enrolment ID, listed above. Being enrolled means the provider can bill Medicare; it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
Licensed in 2 states
This provider holds licences in 2 states: Montana and Washington. The practice address on file is in Tacoma, WA, but a licence in another state usually means they see patients there too — either at a second location or by telehealth. If the address above is far from you, it is worth calling to ask whether they practise closer to where you live.
- Licence
- MD.MD.61669853
- Specialty
- Family Medicine Physician
Licence numbers are self-reported to NPPES at registration. They do not confirm a licence is currently active, in good standing, or valid for the specialty shown — only the state board can tell you that, which is why we link to each one.
What Family Medicine covers
Family Medicine is the medical specialty which is concerned with the total health care of the individual and the family. It is the specialty in breadth which integrates the biological, clinical, and behavioral sciences. The scope of family medicine is not limited by age, sex, organ system, or disease entity. NUCC Health Care Provider Taxonomy, code 207Q00000X
All registered taxonomy codes
This provider registers 2 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 207Q00000X | Family Medicine Physician | MD.MD.61669853 | WA | primary |
| 207Q00000X | Family Medicine Physician | 101180 | MT |
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 | 1538665542 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Mar 30, 2018 |
| Last updated | Sep 4, 2025 |
| Status | Active |
| Sole proprietor | Yes |
| Credential | M.D. |
| Practice address |
1112 6TH AVE 3-TFM Tacoma, WA 98405 (253) 792-6680 Fax (253) 403-2915 |
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 | 5 | 3 | 8 | 6 | 6 | 5 | 5 | 4 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 5 | 6 | 8 | 3 | 6 | 1 | 5 | 8 |
Sum = 68 · next multiple of 10 = 70 · 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.