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C4 Complement
MessagePerforming Lab: Central Lab
Test Code
0454
Alias/See Also
Sunquest: C4
CPT Codes
86160
Preferred Specimen
3 uL Lithium Heparin Plasma (light green-top) tube
Minimum Volume
3 uL (does not include dead volume)
Other Acceptable Specimens
Serum separator (gold-top), Red, Red/Gray
Transport Temperature
Refrigerated
Specimen Stability
Refrigerated: < 2 days
Methodology
Immunoturbidimetric
Setup Schedule
Monday - Friday
Report Available
Same day.
Reference Range
Female: 15 - 57 mg/dL
Male: 15 - 53 mg/dL
Male: 15 - 53 mg/dL
Clinical Significance
C4 is one of the activating enzymes of the complement system. Activation of C4 leads to formation of the C3 convertase in the classical pathway. C4 plays a contributing role in tissue cell damage and inflammation in immunologic disorders. Depressed levels of C4 due to increased consumption may be found in systemic lupus erythematosus (SLE), hereditary angioedema, autoimmune hemolytic anemia, and autoimmune nephritides. A genetic deficiency of C4 is associated with a high prevalence of autoimmune or collagen vascular disease, especially SLE. As an acute-phase reactant, modestly increased levels may occur in inflammation, trauma, and tissue necrosis.
