Complement C3
Complement C3 is a protein that is part of the complement system, a group of proteins that work together to support the immune response. C3 is the most abundant complement protein in the blood.
Category: Inflammation & Immune
Also known as: complement c3, c3, c3 complement, serum c3, Beta 1 C-globulin, komplement c3
Reference range: 90–180 mg/dL (Source: ABIM)
Standard unit: mg/dL
High values may indicate
High C3 levels may indicate acute inflammation, infection, or certain cancers. C3 acts as an acute phase reactant that increases during inflammatory responses.
Low values may indicate
Low C3 levels may indicate systemic lupus erythematosus (SLE), glomerulonephritis, severe liver disease, inherited complement deficiency, or active autoimmune disease consuming complement proteins.
Frequently asked questions
- What is a normal Complement C3 level?
- A typical reference range for Complement C3 is 90–180 mg/dL (source: ABIM). Reference ranges vary by laboratory, age, and sex, so always compare against the range on your own lab report.
- What units is Complement C3 measured in?
- Complement C3 is most commonly reported in mg/dL. Labs in different countries may use other units — you can convert between them with BloodId's blood test unit converter.
- Where do Complement C3 reference ranges come from?
- BloodId uses ABIM standard reference ranges and educational information from MedlinePlus (see our methodology). Reference ranges still vary by lab, age, and sex, so always compare against your own report.
- Can I track Complement C3 over time?
- Yes. Upload results from any lab and BloodId charts your Complement C3 over time against its reference range, so you can see whether the trend is rising, falling, or stable.
Related biomarkers
Source: MedlinePlus, U.S. National Library of Medicine
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