Thomas Keith Duncan, MD
Internal Medicine Physician · Neenah, WI
Thomas Keith Duncan, MD is an internal medicine physician with a practice address in Neenah, Wisconsin, and NPI 1588641039, issued on Dec 27, 2005. Check the license (Wisconsin 22196, as entered in NPPES) on the Wisconsin Medical Examining Board; the Medicare figures below come from public CMS files.
- Name
- Thomas Keith Duncan
- Credential
- MD
- Primary taxonomy
- Internal Medicine Physician 207R00000X
- License number
- 22196 WI
Self-reported in NPPES; status is on the state search - Practice location
- 200 Theda Clark Medical Plz Ste 240, Neenah, WI 54956
- Phone
- (920) 725-2070
- Enumerated
- Dec 27, 2005
- Record last updated
- Nov 23, 2011 (not updated in 15 years: call before relying on the address or phone)
- Medicaid ID
- 30252000 WI
- Medicare enrollment
- Enrolled (PECOS I20070215000018); accepts Medicare assignment
- Medical or professional school
- Northwestern University Feinberg Medical School, 1975
- Telehealth
- Offers telehealth (CMS)
- Entity
- Type 1 · individual
8 nearest internal medicine physician records → All 2,078 in Wisconsin → Look up another NPI →
Also registered at 200 Theda Clark Medical Plz Ste 240
A shared address usually means a shared clinic or building; it does not show who employs whom.
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Verify Thomas Keith Duncan in five checks
- 1IdentityNPI record in CMS NPPESNPI lookupConfirmed in NPPES
- 2LicenseActive license and public ordersWisconsin Medical Examining Board
Search for license 22196Check the board - 3Other statesLicenses and actions elsewhereDocInfo (FSMB)Not checked
- 4ExclusionsMedicare and Medicaid bansHHS-OIG exclusion listNot checked
- 5CertificationBoard certificationABMS AOA NCCPA AANPNot checked
2.9 times the Medicare Part D claims of the average internal medicine physician in 2024
9,289 Medicare Part D claims for 587 beneficiaries, against an average of 3,176 among the 108,855 providers of this specialty who prescribed in Part D. Brand-name drugs were 10% of claims. 122 claims were for opioids.
Most prescribed
- Atorvastatin Calcium479 claims
- Amlodipine Besylate367 claims
- Omeprazole337 claims
- Lisinopril336 claims
- Hydrochlorothiazide280 claims
- Levothyroxine Sodium274 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.
Bills Medicare through one group practice
- Thedacare, IncorporatedNew London, WI
Source: CMS Doctors and Clinicians National Downloadable File (the group practices a clinician bills Medicare through) (data.cms.gov).
Thomas Keith Duncan among 2,078 internal medicine physician records in Wisconsin
Thomas Keith Duncan, MD is one of 2,078 internal medicine physician records with a practice address in Wisconsin. 70% 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, 91% newer
- In a Medicare fileYes · 70% of these records are
- In the CMS Doctors and Clinicians fileYes · 53% of these records are
- Graduated1975 · median 2002 among the 1,098 with a school on file
- Record last updated2011 · 55% of these records were not updated in five years or more
Source: CMS NPPES, file of Aug 9, 2026, every record with primary taxonomy 207R00000X and a Wisconsin practice address; Medicare files: CMS Part D Prescribers 2024, MIPS 2023, Open Payments 2024, Doctors and Clinicians (data.cms.gov).
22 internal medicine physician records list a practice address in Neenah
They are 22 of the 919 NPPES records with a practice address in Neenah, and 2,078 internal medicine physician records in Wisconsin.
All 2,078 in Wisconsin → Every provider in Neenah → Internal Medicine Physician nationwide →
The 8 internal medicine physician records with the nearest ZIP codes
- Curtis Baltz, MDNeenah, WI 549561316939325
- Michael Beckett, MDNeenah, WI 549561417941337
- James Burns, MDNeenah, WI 549561225022080
- Mark Hermans, MDNeenah, WI 549561386676948
- Roxanne Jadin Cardelli, MDNeenah, WI 549561750339040
- Steven Knaus, MDNeenah, WI 549561457332215
- Paul McAvoy, MDNeenah, WI 549561992799779
- William Nelson, MDNeenah, WI 549561154316396
Common questions
What is Thomas Keith Duncan, MD's NPI number?
Thomas Keith Duncan, MD's National Provider Identifier (NPI) is 1588641039, issued on Dec 27, 2005. An NPI identifies a provider in billing; it is not a license.
Where is Thomas Keith Duncan, MD located?
The NPPES record lists a practice address at 200 Theda Clark Medical Plz Ste 240, Neenah, WI, 54956. Phone: (920) 725-2070. Providers update this record themselves, so call before visiting.
How can I verify Thomas Keith Duncan, MD's license?
NPPES lists Wisconsin license number 22196, as entered by the provider. Search the Wisconsin Medical Examining Board at https://dsps.wi.gov/Pages/BoardsCouncils/MEB/Default.aspx. The NPPES record confirms identity only; the state search shows license status, expiration and public orders.
How much does Thomas Keith Duncan, MD prescribe under Medicare Part D?
In 2024, Thomas Keith Duncan, MD had 9,289 Medicare Part D claims for 587 beneficiaries; the average among internal medicine physician prescribers was 3,176. 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.