Mark Duncan, MD
NPI 1598713919 · Family Medicine Physician · Freeland, WA
Enrolled with Medicare as Practitioner - Family Practice · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Mark Duncan, MD is a Family Medicine Physician provider in Freeland, WA (NPI 1598713919).
Provider details
- NPI number
- 1598713919
- Entity type
- Individual
- Primary specialty
- Family Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 045063 (GA)
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 tenure38% of score
20 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
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 prescribes (Medicare Part D)
Top drugs by Medicare Part D claim volume, 2024 · 27 distinct drugs on file.
| Drug | Part D claims (2024) | Beneficiaries |
|---|---|---|
| Atorvastatin Calcium | 94 | 43 |
| Lisinopril | 48 | 26 |
| Amlodipine Besylate | 44 | 20 |
| Losartan Potassium | 40 | 21 |
| Metformin Hcl | 38 | 16 |
| Omeprazole | 37 | 18 |
| Levothyroxine Sodium |
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-05-05
- Last updated
- 2023-04-25
- Certified
- 2023-04-25
Frequently asked questions
- What is Mark Duncan's NPI number?
- Mark Duncan's National Provider Identifier (NPI) is 1598713919, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Mark Duncan's specialty?
- Mark Duncan is listed in the NPPES registry with a primary specialty of Family Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Mark Duncan located?
- Mark Duncan's practice location on file with NPPES is 5577 Vanbarr Pl, Freeland, WA 98249-9555.
- What is Mark Duncan's phone number?
- The practice phone number listed in the NPPES registry for Mark Duncan is (360) 331-3343.
- Does Mark Duncan accept Medicare?
- Mark Duncan is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Mark Duncan's NPI active?
- Yes — Mark Duncan's NPI (1598713919) is active in the NPPES registry as of the last update on 2023-04-25.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.