Complement 4 is one of the activation proteins taking part in the classical pathway of the complement system involved in innate and adaptive immunity. The activation of pathways is related to the utilization of C4, thereby reducing its concentration. Complement 4 test measures the amount of C4 proteins in the blood. Decreased levels of C4 are generally associated with angioedema, autoimmune hemolytic anemia, lupus, and rheumatoid arthritis. This test is also used to monitor protein levels in people who have already been diagnosed with an autoimmune disease. We offer Complement 4 at the most affordable price. Sample collection at home available.