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

Marcus Clark

Individual provider Rheumatology Physician · NPI 1790847242

Marcus Clark practises Rheumatology in Chicago, Illinois. Qualified in 1984, 42 years ago. Practices with University of Chicago, a 1,681-clinician group and accepts Medicare assignment. Licensed in Illinois.

Years since qualifying
42
Licensed in
IL
In the registry since
2006
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Practice location Address checks out

5841 S Maryland Ave
Chicago, IL 60637-1443
Phone: (888) 824-0200
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Pin is approximate — placed at the ZIP-code centre, not the exact door.

Specialties & licences

Rheumatology Physician (primary) Taxonomy 207RR0500X · Licence 036087330 (IL)

Record details

NPI number1790847242
Entity typeIndividual (Type 1)
GenderMale
Sole proprietorNo
NPI enumeratedDecember 14, 2006
Last updated in NPPESOctober 24, 2022

Medicare enrollment

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

Medicare specialtyRHEUMATOLOGY
Also practisesINTERNAL MEDICINE
Medical schoolOTHER
Graduated 1984 (42 years in practice)
Group practice University Of Chicago — 1681 clinicians
Accepts Medicare assignment Yes — accepts the Medicare-approved amount

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 patients11
Services billed 16 a service is one billed item, such as a visit, a test or a procedure
Average patient age57

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.

Payments from drug and device companies, 2025

Drug and device makers are required by federal law (the Physician Payments Sunshine Act) to report what they pay or give to clinicians, and CMS publishes the reports as Open Payments. This is the 2025 program year. A report is a record of a payment, not an allegation of anything, and many are small items such as meals. Only general payments are listed here; research payments and ownership or investment interests are reported separately by CMS and are not shown.

Food and Beverage $24 1 payment · a meal or drink at a meeting or visit, not a fee

Each amount is the sum of what companies reported for that kind of payment in 2025, rounded to the dollar. Not all of it is income to the clinician: a meal is not a fee, a charitable contribution goes to a charity, and a royalty or an acquisition payment is not a salary.

Check a report, or dispute one, at the source in CMS’s own tool, Open Payments. Corrections go through CMS’s dispute process. This site removes a home address on request and asks for no proof, because that is privacy; it will not remove an accurate payment report on request, because that is a statutory public disclosure.

Practises at

Facilities the CMS Facility Affiliation file lists for this clinician.

Colleagues at University of Chicago

Clinicians the CMS Doctors & Clinicians file lists under the same group practice. CMS counts 1681 clinicians in the practice; 12 are shown here.

Other providers in Chicago