Complement C4 Blood Test

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Feature	Labcorp	Quest Diagnostics
Price	$17.49	$17.49
Results in	~2 business days	~5 business days
Sample type	Blood Serum	Blood Serum
Require fasting	No	No

About the test

Complement C4 is a blood protein that is part of the complement system, which supports the immune response by helping to fight infections and remove damaged cells. A C4 test is often used to help diagnose or monitor autoimmune conditions like systemic lupus erythematosus (SLE) and hereditary angioedema.

Included biomarkers & Reference ranges

Biomarker	Reference range
Complement Component C4c A complement system protein involved in immune defense. Low levels are associated with active autoimmune conditions like lupus, or certain genetic deficiencies.	—

Reference ranges vary by lab, age, and sex (M/F). Your report shows your exact range. Click any biomarker to see its optimal range and what your results mean.

How it works

1. Order online No referral or insurance
2. Get a requisition By email in 24–72 hours
3. Visit a draw center Bring a matching photo ID
4. Get results Securely by email

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Consultations

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Schedule a consultation with a Hormunity specialist. We’ll walk through every marker, interpret what it means for you, and map out the next steps for your care.

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