Marcus Clark appears in the CMS NPPES registry as a Rheumatology Physician provider at 5841 S MARYLAND AVE, Chicago, IL, 60637, with a listed phone of (888) 824-0200. NPI 1790847242 was issued on 12/14/2006.

Medicare Part D prescribing data is not currently published for this NPI, which typically means the provider either wrote fewer than 11 Part D claims in the most recent reporting year, does not participate in Medicare, or practices in a specialty that rarely prescribes outpatient drugs. Absence of prescribing data is not a quality signal, many Rheumatology Physician providers operate outside Part D entirely.

Rheumatology Physician is a mid-sized specialty nationwide, with 6,181 enrolled providers across 52 states and an average of 2,054 Part D claims per prescriber, so the context for interpreting these metrics differs meaningfully from a primary-care baseline.

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