The purpose of this test is to:
The Complement C4 Level Test measures the amount of Complement Component 4 (C4), an important protein in the complement system that plays a key role in the body's immune response. C4 helps the immune system identify and eliminate bacteria, viruses, and other harmful microorganisms while also supporting the removal of damaged cells and immune complexes. Measuring C4 levels provides valuable information about immune system activity and helps identify abnormalities associated with autoimmune and inflammatory conditions.
This test is commonly used alongside the Complement C3 Test and other laboratory investigations to diagnose and monitor autoimmune diseases such as Systemic Lupus Erythematosus (SLE), rheumatoid arthritis, vasculitis, and certain kidney disorders. Low C4 levels may indicate increased complement consumption due to active autoimmune disease, hereditary angioedema, or chronic infections, while elevated levels may occur in some inflammatory conditions. Healthcare providers may also recommend this test to monitor disease activity, evaluate treatment response, and investigate recurrent infections or unexplained inflammation. The results should always be interpreted along with clinical symptoms, medical history, and other diagnostic tests for a comprehensive assessment.
1. What is the Complement C4 Level Test used for?
The Complement C4 Level Test measures the amount of C4 protein in the blood to evaluate immune system function. It helps diagnose and monitor autoimmune diseases, inflammatory conditions, hereditary angioedema, and certain kidney disorders.
2. Do I need to fast before the Complement C4 Level Test?
No. Fasting is generally not required before the Complement C4 Level Test. However, you should follow any specific instructions provided by your healthcare provider or diagnostic laboratory.
3. What does a low Complement C4 level indicate?
A low C4 level may be associated with autoimmune diseases such as lupus, hereditary angioedema, chronic infections, or increased complement consumption due to ongoing immune system activity. Your doctor will interpret the results along with other clinical findings and laboratory tests.