Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of August 10, 2026.
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Dr. Thomas Michael Defer, MD

Individual provider Internal Medicine Physician · NPI 1023036464

Dr. Thomas Michael Defer, MD is an Internal Medicine in Saint Louis, Missouri. Graduated from University of Missouri, Columbia School of Medicine in 1989, 37 years ago. Practices with Washington University, a 2,986-clinician group and accepts Medicare assignment. Licensed in Missouri.

Years since qualifying
37
Trained at
University of Missouri, Columbia School of Medicine
Licensed in
MO
In the registry since
2006
What do these letters mean?
MD — Doctor of Medicine
A physician who completed allopathic medical school.

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Practice location Address checks out

4950 Childrens Pl Dept Internal Med
Saint Louis, MO 63110-1000
Phone: (314) 362-5060
Fax: (314) 362-6959
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Internal Medicine Physician (primary) Taxonomy 207R00000X · Licence R4N34 (MO)

Record details

NPI number1023036464
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedJuly 17, 2006
Last updated in NPPESApril 17, 2025

Medicare enrollment

From the CMS Doctors & Clinicians file — this clinician is enrolled in Medicare.

Medicare specialtyINTERNAL MEDICINE
Medical schoolUNIVERSITY OF MISSOURI, COLUMBIA SCHOOL OF MEDICINE
Graduated 1989 (37 years in practice)
Group practice Washington University — 2986 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
Practice locations2 on file with Medicare

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