The Complement C3 + C4 test is a blood test used to measure the levels of complement proteins C3 and C4 in the blood. Complement proteins C3 and C4 are key components of the complement system, a group of proteins that play a central role in the innate immune response, inflammation, and host defense against pathogens.
Overview:
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Indication: Assesses various immune-mediated and inflammatory conditions, including autoimmune diseases, complement deficiencies, and kidney diseases. It helps assess the activity and functionality of the complement system and provides valuable information about the patient's immune status and disease activity.
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Procedure: Blood serum is tested for the levels of complement proteins C3 and C4 using quantitative assays, such as nephelometry or turbidimetry, which measure the amount of light scattered or absorbed by immune complexes formed between complement proteins and specific antibodies.
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Results: Decreased levels of may indicate complement activation and consumption, as seen in conditions such as systemic lupus erythematosus (SLE), glomerulonephritis, or complement deficiencies. Elevated levels may occur in acute-phase reactions, inflammation, or certain infections.