Description
Why It’s Done
The test is ordered to:
1. Diagnose and Monitor Autoimmune Diseases
• Conditions like systemic lupus erythematosus (SLE), rheumatoid arthritis, and other autoimmune disorders often show low C3 levels during active disease.
2. Detect Complement Deficiencies
• To identify inherited or acquired deficiencies that may increase susceptibility to infections.
3. Assess Disease Activity
• Helps monitor disease progression or response to treatment in autoimmune conditions.
4. Investigate Kidney Diseases
• Some kidney diseases such as glomerulonephritis involve changes in complement levels, including C3.
Preparation
1. Fasting
• Usually, no fasting is required.
2. Medications
• Inform your healthcare provider about any medications, especially immunosuppressants or steroids.
3. Sample Collection
• A blood sample is drawn from a vein, typically in your arm.
• The procedure is quick and minimally invasive.
