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Complement C4
Test CodeC4
Alias/See Also
Epic: LAB151
Preferred Specimen
Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 3 mL
Minimum Volume
0.25 mL
Instructions
Centrifuge and separate cells after clot formation and within 4 hours of collection
Transport Container
Plastic vial
Specimen Stability
Room temperature: Unacceptable
Refrigerated: 2 days
Frozen: Unacceptable
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Unlabeled, mislabeled, wrong tube type, hemolyzed, visually lipemic, QNS, exceeds specimen/stability requirements.
Methodology
Immunoturbidimetric
Setup Schedule
Daily
Report Available
Same day
Limitations
Samples containing paraproteins (abnormal monoclonal antibodies) may incorrectly fall within the reference range. Samples with elevated total protein concentrations or suspected paraproteinemia can be screened with other methods such as electrophoresis. Turbidity and particles in samples can interfere with the assay. Therefore, particulate matter should be removed by centrifugation prior to running the assay.
Reference Range
| 1-14 years | Male: | 13-44 mg/dL |
| Female: | 13-46 mg/dL | |
| >14 years | Male: | 15-53 mg/dL |
| Female: | 15-57 mg/dL |
Clinical Significance
All complement components are acute phase reactants and rise rapidly during inflammation episodes. The rates of complement protein catabolism may increase in various autoimmune diseases.
Complement promotes inflammation or tissue damage during the immune response, and plays an important role in the pathogenesis of some diseases.
Increased C4 levels occur in individuals with acute phase reactions and certain malignancies.
C4 levels may be decrease in hereditary and acquired angioedema, complement activation due to liver disease, increased consumption in glomerulonephritis, SLE, rheumatoid arthritis, respiratory distress syndrome, autoimmune hemolytic anemia, cryoglobulinemia, and sepsis.
Partial and complete congenital C4 deficiencies have been associated with immune complex diseases, SLE, autoimmune thyroiditis, and juvenile dermatomyositis.
Infections associated with C4 deficiency include bacterial or viral meningitis, Streptococcus and Staphylococcus sepsis, and pneumonia.
Complement promotes inflammation or tissue damage during the immune response, and plays an important role in the pathogenesis of some diseases.
Increased C4 levels occur in individuals with acute phase reactions and certain malignancies.
C4 levels may be decrease in hereditary and acquired angioedema, complement activation due to liver disease, increased consumption in glomerulonephritis, SLE, rheumatoid arthritis, respiratory distress syndrome, autoimmune hemolytic anemia, cryoglobulinemia, and sepsis.
Partial and complete congenital C4 deficiencies have been associated with immune complex diseases, SLE, autoimmune thyroiditis, and juvenile dermatomyositis.
Infections associated with C4 deficiency include bacterial or viral meningitis, Streptococcus and Staphylococcus sepsis, and pneumonia.
Performing Laboratory
Inova Laboratories
2832 Juniper Street
Fairfax, VA 22031
Last Updated: March 6, 2023
Last Review: N. Wolford, March 6, 2023