Douglas Duffy, MD
NPI 1366542227 · Nephrology Physician · Marshfield, WI
Douglas Duffy, MD is a Nephrology Physician provider in Marshfield, WI (NPI 1366542227).
Provider details
- NPI number
- 1366542227
- Entity type
- Individual
- Primary specialty
- Nephrology PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- 25241 (WI)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
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
19 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
2 documented practice locations
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.
Practice location
Mailing address
Additional practice locations (1)
- 801 Broadway NFargo, ND 58102-3641Phone: (701) 234-2000
Registry dates
- Enumerated
- 2006-09-22
- Last updated
- 2018-08-01
Frequently asked questions
- What is Douglas Duffy's NPI number?
- Douglas Duffy's National Provider Identifier (NPI) is 1366542227, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Douglas Duffy's specialty?
- Douglas Duffy is listed in the NPPES registry with a primary specialty of Nephrology Physician (Allopathic & Osteopathic Physicians).
- Where is Douglas Duffy located?
- Douglas Duffy's practice location on file with NPPES is 1000 N Oak Ave, Marshfield, WI 54449.
- What is Douglas Duffy's phone number?
- The practice phone number listed in the NPPES registry for Douglas Duffy is (715) 387-5345.
- Is Douglas Duffy's NPI active?
- Yes — Douglas Duffy's NPI (1366542227) is active in the NPPES registry as of the last update on 2018-08-01.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.