Complement C3 and C4 panel
A complement blood test measures the levels and/or activity of a group of proteins that are part of the complement system. This system "complements" or enhances your body's defenses against infections and other diseases. Your immune system makes antibodies, which are proteins to fight disease-causing substances like viruses and bacteria.
Source: MedlinePlus, U.S. National Library of Medicine2 tests in this panel
| Test | Unit | Normal range | Source |
|---|---|---|---|
| Complement C3 | mg/dL | 75–180 mg/dL * | ARUP Laboratories Test Directory, Mayo Clinic Laboratories (Pediatric Test Catalog), Mayo Clinic Laboratories (Test Catalog) |
| Complement C4 | mg/dL | 10–40 mg/dL * | ARUP Laboratories Test Directory, Mayo Clinic Laboratories (Pediatric Test Catalog), Mayo Clinic Laboratories (Test Catalog) |
Adult reference ranges, attributed to the labs that publish them; * marks a range that varies by sex or age — see the test for the full breakdown. A dash means we hold no cited adult range for that test yet.