Isaac Fonken, M.D.
NPI 1538665542 · Family Medicine Physician · Tacoma, WA
Enrolled with Medicare as Practitioner - Family Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Isaac Fonken, M.D. is a Family Medicine Physician provider in Tacoma, WA (NPI 1538665542).
Provider details
- NPI number
- 1538665542
- Entity type
- Individual
- Primary specialty
- Family Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Male
- Sole proprietor
- Yes
- License
- 101180 (MT)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure28% of score
8 yrs in NPPES registry
- Profile completeness28% of score
100% of core fields populated
- Practice footprint17% of score
1 documented practice location
- Medicare service volume (vs. specialty peers)28% of score
23 Medicare services, 2024 (ranked within specialty)
Medicare volume is ranked against active providers in the same specialty. Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
What this provider does (Medicare)
Based on Medicare fee-for-service claims, 2024; not all care is captured.
| Service (HCPCS) | Medicare services | Typical Medicare-allowed (2024) |
|---|---|---|
| Subsequent Hospital Care With Moderate Levelof Medical Decision Making, If Using Time, at Least 35 Minutes99232 | 23 | $76 |
Typical Medicare-allowed amounts for these services range $76–$76 (2024). The Medicare-allowed amount is what Medicare recognizes for a service under fee-for-service — a reference figure for 2024, not a price quote and not what you would be billed. Medicare Part B covers roughly an eighth of all NPIs (65+ skew); services with fewer than 11 beneficiaries are suppressed by CMS. Source: CMS Medicare Physician & Other Practitioners, by Provider & Service.
What this provider prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 67 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Levothyroxine Sodium | 117 | — |
| Losartan Potassium | 111 | 18 |
| Empagliflozinbrand: Jardiance | 110 | — |
| Gabapentin | 87 | — |
| Apixabanbrand: Eliquis | 84 | — |
| Sertraline Hcl | 77 | — |
Practice location
Mailing address
Registry dates
- Enumerated
- 2018-03-30
- Last updated
- 2025-09-04
- Certified
- 2025-09-04
Frequently asked questions
- What is Isaac Fonken's NPI number?
- Isaac Fonken's National Provider Identifier (NPI) is 1538665542, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Isaac Fonken's specialty?
- Isaac Fonken is listed in the NPPES registry with a primary specialty of Family Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Isaac Fonken located?
- Isaac Fonken's practice location on file with NPPES is 1112 6th Ave, Tacoma, WA 98405-4040.
- What is Isaac Fonken's phone number?
- The practice phone number listed in the NPPES registry for Isaac Fonken is (253) 792-6680.
- Does Isaac Fonken accept Medicare?
- Isaac Fonken is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Isaac Fonken's NPI active?
- Yes — Isaac Fonken's NPI (1538665542) is active in the NPPES registry as of the last update on 2025-09-04.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.