Doctor profile · Federal record

Dr. Douglas Duffy, MD

Nephrology Physician · Internal Medicine Physician · Nephrology Physician · Marshfield, WI

  • NPI 1366542227
  • 20 yrs on file
  • Licensed in 2 states
  • Male
  • Group practice
  • No sanctions

Practice & contact

Operates at 2 locations .

NPPES Updated May 11, 2026
Primary practice
1000 N Oak Ave
Marshfield, WI 54449
(715) 387-5345
Additional location
801 Broadway N
Fargo, ND 581023641
(701) 234-2000

Credentials & registration

NPPES · NUCC
NPI registered
September 2006 — 20 yrs on file
Profile last updated
August 1, 2018
Specialty taxonomy
207RN0300X — NUCC code
State licenses (2)
Wisconsin #25241 · North Dakota #LT15265
Medicaid
WI #30517100

Federal sanctions & exclusions

OIG LEIE Updated May 11, 2026

No sanctions, exclusions or revocations on file

Checked against OIG LEIE on NPI 1366542227. Last verified May 11, 2026.

Medicare procedures · 2023

Top services delivered

CMS Provider Utilization
Total services
29
Distinct HCPCS
1
Medicare allowed
$2,202
HCPCS Description Services Patients Avg allowed
99232 Subsequent hospital care with moderate levelof medical decision making, if using time, at least 35 minutes 29 12 $76

In context: peer comparison

Among 5 peers in Marshfield Nephrology Physician, average services per provider: 75. This provider delivers 0.4× the peer median.

Frequently asked questions

Auto-generated from federal data
What is Dr. Douglas Duffy's medical specialty?
Dr. Douglas Duffy practices Nephrology Physician in Marshfield, WI.
Where does Dr. Douglas Duffy practice?
Dr. Douglas Duffy practices at 1000 N Oak Ave, Marshfield, WI 54449. Office phone: 7153875345.
What is Dr. Douglas Duffy's NPI?
Dr. Douglas Duffy's National Provider Identifier (NPI) is 1366542227, issued by NPPES.
What procedures does Dr. Douglas Duffy commonly perform?
Top Medicare-reported procedures in 2023: Subsequent hospital care with moderate levelof medical decision making (HCPCS 99232). Source: CMS Medicare Physician & Other Practitioners file.