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A member asked:

Complement c3 and c4 tests done 3 times due to lupus symptoms. c3 always normal but c4 borderline low twice, now normal. is this a deficiency?

A doctor has provided 1 answer
Dr. Joram Seggev answered

Specializes in Internal Medicine - Allergy & Immunology

Disease activity: I assume that the diagnosis of sLE has been confirmed. The concentration of C4 is much lower than C3. As C4 is ow normal, there is no deficiency. When sLE is active, C4 concentration may decrease because of it being used up by immune complexes in the blood. When disease activity lessens, less C4 is being used.

Answered 8/24/2018

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