William Brian Duffy, MD
Nephrology Physician · Chicago, IL
William Brian Duffy, MD is a nephrology physician with a practice address in Chicago, Illinois, and NPI 1568448363, issued on Dec 22, 2005. Check the license (Illinois 036057381, as entered in NPPES) on the Illinois Department of Financial and Professional Regulation; the Medicare figures below come from public CMS files.
- Name
- William Brian Duffy
- Credential
- MD
- Primary taxonomy
- Nephrology Physician 207RN0300X
- License number
- 036057381 IL
Self-reported in NPPES; status is on the state search - Practice location
- 1101 S Canal St, Chicago, IL 60607
- Phone
- (312) 986-0110
- Enumerated
- Dec 22, 2005
- Record last updated
- Jan 3, 2012 (not updated in 14 years: call before relying on the address or phone)
- Fax
- (312) 663-1010
- Medicaid ID
- 036057381 IL
- Entity
- Type 1 · individual
8 nearest nephrology physician records → All 572 in Illinois → Look up another NPI →
Also registered at 1101 S Canal St
A shared address usually means a shared clinic or building; it does not show who employs whom.
- Brett Curtiss, R.D., L.D.N.Renal Nutrition Registered Dietitian1073904488
- Chelsea FournierFamily Medicine Physician1114581501
- Elizabeth Graves, D.C.Chiropractor1609008135
- Paru Kathpalia, MDNephrology Physician1689864787
- Loyal Nelson, D.C.Chiropractor1437329885
- Nikulkumar Patel, O.D.Optometrist1245528140
Verify William Brian Duffy in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersIllinois Department of Financial and Professional Regulation
Search for license 036057381Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
99% fewer Medicare Part D claims than the average nephrology physician in 2024
12 Medicare Part D claims, against an average of 1,465 among the 10,986 providers of this specialty who prescribed in Part D. Brand-name drugs were 0% of claims.
Source: CMS Medicare Part D Prescribers by Provider and Drug, 2024 (data.cms.gov). Part D covers prescriptions for Medicare patients only; drugs with fewer than 11 claims are not published.
William Brian Duffy among 572 nephrology physician records in Illinois
William Brian Duffy, MD is one of 572 nephrology physician records with a practice address in Illinois. 87% of them appear in a Medicare file (Part D prescribing, MIPS, Open Payments or Medicare group billing); this one does. Its NPI, issued in 2005, is newer than 0% of them.
- NPI issued2005 · 0% of these records are older, 88% newer
- In a Medicare fileYes · 87% of these records are
- In the CMS Doctors and Clinicians fileNo · 76% of these records are
- Record last updated2012 · 39% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207RN0300X and a Illinois practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
Nephrology Physician providers in Illinois
There are 572 nephrology physician records in Illinois.
All 572 in Illinois → Every provider in Chicago → Nephrology Physician nationwide →
The 8 nephrology physician records with the nearest ZIP codes
- Pravir Baxi, M.D.Chicago, IL 606071780970731
- Juan Jose Cintron Garcia, MD, MPHChicago, IL 606071841693728
- Chaudhry Hamood Dhillon, MDChicago, IL 606071306331277
- Casey Gashti, MDChicago, IL 606071285762252
- Paru Kathpalia, MDChicago, IL 606071689864787
- Stephen Korbet, MDChicago, IL 606071972608289
- Jennifer Lazor, D.O.Chicago, IL 606071346515871
- Roger Rodby, MDChicago, IL 606071043327927
Common questions
What is William Brian Duffy, MD's NPI number?
William Brian Duffy, MD's National Provider Identifier (NPI) is 1568448363, issued on Dec 22, 2005. An NPI identifies a provider in billing; it is not a license.
Where is William Brian Duffy, MD located?
The NPPES record lists a practice address at 1101 S Canal St, Chicago, IL, 60607. Phone: (312) 986-0110. Providers update this record themselves, so call before visiting.
How can I verify William Brian Duffy, MD's license?
NPPES lists Illinois license number 036057381, as entered by the provider. Search the Illinois Department of Financial and Professional Regulation at https://idfpr.illinois.gov/checklicense.html. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does William Brian Duffy, MD prescribe under Medicare Part D?
In 2024, William Brian Duffy, MD had 12 Medicare Part D claims; the average among nephrology physician prescribers was 1,465. Part D covers Medicare prescriptions only.
Source: CMS National Plan and Provider Enumeration System (NPPES), file of Aug 9, 2026 (NPPES files on CMS.gov); NUCC Health Care Provider Taxonomy. Medicare files from data.cms.gov. An NPI identifies who bills; it is not a license.
Figures on PlainDoctor are read from the federal files each page names (CMS NPPES, Medicare Part D, MIPS, Open Payments; the HHS-OIG exclusion list only as counts) and from Census population estimates, with the file date shown beside them. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of Aug 9, 2026.