Advanced Diagnostic Laboratories

C4 Function

Test Code

C4F

Description

The complement system is part of our innate immune response. It is vital to our defense against invasive microorganisms. Complement activation can occur through the classical, lectin and alternative pathway, which then converge to a common terminal pathway. Complement deficiency can lead to life-threatening infections well as long-term autoimmune conditions such as systemic lupus erythematosus (SLE) and hereditary angioedema (HAE).

The C4 hemolytic assay is a sensitive method for detection classical complement protein C4 activity or lack thereof. Severe or recurrent infections that produce strong activation of the classical complement pathway may lower C4 activity below normal. Genetic or acquired complement deficiency involving the classical complement pathway components C4 may also lower C4 activity as well as CH50 activity.

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