Description
C4, primarily produced by hepatocytes, is involved in both the alternative and classical complement pathways. C4 has a similar overall structure to that of C3.
Indications
Increased C4 levels are found in association with C1 (q, r, or s) deficiency, and the presence of more than four C4 alleles. Acquired conditions in which C4 levels are increased include acute phase reactions and certain malignancies. Total or partial C4 deficiency are is associated with immune complex disease, SLE, autoimmune thyroditis, and juvenile dermatomyositis. In addition, C4 levels are decreased in bacterial or viral meningitis, Streptococcus and Staphylococcus sepsis, and pneumonia.
Sample Type, Quantity & Conditions
1 ml Serum 1 ml K3-EDTA or Li, NH4+-Heparin Plasma Stability: 2 Days at 15-25 °C 2 Days at 2-8 °C
Special Precautions
Separate serum/plasma from cells as soon as possible.
Normal Range
10 - 40 mg/dL 0.1 - 0.4 g/L
