Provider records sourced from NPPES (CMS National Plan & Provider Enumeration System). Data current as of October 4, 2026.
NPIDirectory

Dr. Colin E Diffie, MD

Individual provider Rheumatology Physician · NPI 1942616404

Dr. Colin E Diffie, MD practises Rheumatology in Saint Louis, Missouri. Qualified in 2014, 12 years ago. Practices with Washington University, a 2,986-clinician group, works from 2 locations, accepts Medicare assignment and offers telehealth. Licensed in Missouri.

Years since qualifying
12
Licensed in
MO
In the registry since
2014
Specialties on file
2
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

915 N Grand Blvd
Saint Louis, MO 63106-1621
Phone: (314) 652-4100
Fax: (314) 289-6442
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Additional practice locations (1)

  • 4921 Parkview Pl, Saint Louis, MO 63110-1032 — (314) 286-2635

Specialties & licences

Rheumatology Physician (primary) Taxonomy 207RR0500X · Licence 2019017299 (MO)
Internal Medicine Physician Taxonomy 207R00000X · Licence 2019017299 (MO)

Record details

NPI number1942616404
Entity typeIndividual (Type 1)
GenderMale
Credentials MD
Sole proprietorNo
NPI enumeratedJuly 5, 2014
Last updated in NPPESSeptember 11, 2025
Certification dateSeptember 11, 2025

Medicare enrollment

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

Medicare specialtyRHEUMATOLOGY
Also practisesINTERNAL MEDICINE
Medical schoolOTHER
Graduated 2014 (12 years in practice)
Group practice Washington University — 2986 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount
TelehealthOffers telehealth services
Practice locations4 on file with Medicare

Medicare patients and services, 2024

From the CMS Medicare Physician & Other Practitioners file for calendar year 2024. It counts Original Medicare patients only, so a practice that mostly sees Medicare Advantage or privately insured patients looks smaller here than it is.

Medicare patients401
Services billed 17,975 a service is one billed item, such as a visit, a test or a procedure
Average patient age70

Dollar amounts are not shown. What Medicare pays a practice is gross billings, before staff, premises and tax and including the cost of any drugs it administers, so it is not what a clinician earns.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician.

Colleagues at Washington University

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 2986 clinicians in the practice; 12 are shown here.

Other providers in Saint Louis