Douglas Duffy, MD

Addiction Medicine · Internal Medicine · Nephrology

20+ years in practiceNPI: 1366542227Licensed in WILicensed in ND

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Credentials & Recognition

Specialties

Addiction MedicineInternal MedicineNephrology

NPI sub-specialties

Internal Medicine207R00000X

Internal Medicine, Nephrology207RN0300X

Internal Medicine, Nephrology207RN0300X

Practice Signals

Editorial signals beyond credentials. Patient transparency over opacity. See methodology.

Mid-Level (PA/NP) Use

Doctor-led visits

Years in Practice

20+ years

Estimated from NPI enumeration date

Featured in PBCMMG Rankings

#5

Top Nephrologists in North Dakota, 2026

Nephrology · North Dakota · 2026

#7

Top Nephrologists in Wisconsin, 2026

Nephrology · Wisconsin · 2026

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Frequently Asked Questions about Dr. Douglas Duffy, MD

Where does Dr. Douglas Duffy, MD practice?+
Dr. Douglas Duffy, MD practices in Wisconsin, WI. 1000 N OAK AVE MARSHFIELD, WI 54449.
What is Dr. Douglas Duffy, MD's phone number?+
Dr. Douglas Duffy, MD's practice phone is 715-387-5345. Office contact information is verified on the PBCMMG profile.
What does Dr. Douglas Duffy, MD specialize in?+
Dr. Douglas Duffy, MD's primary specialty is Addiction Medicine, with additional focus on Internal Medicine, Nephrology.
Is Dr. Douglas Duffy, MD board certified?+
Board certification status for Dr. Douglas Duffy, MD has not been verified in the data sources PBCMMG uses (ABMS, state medical boards). The PBCMMG profile shows their current credential set.
How long has Dr. Douglas Duffy, MD been practicing?+
Dr. Douglas Duffy, MD has been in active practice for 20+ years, based on NPI enumeration and state licensing records.
What is Dr. Douglas Duffy, MD's NPI number?+
Dr. Douglas Duffy, MD's National Provider Identifier (NPI) is 1366542227, registered in the federal NPPES registry.

Profile maintained by Palm Beach County Medical Media Group, Inc. | Data verified from public registries (NPPES, ABMS, state medical boards). Methodology · Editorial Standards

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