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Laboratory Medicine

Test Directory / C4 Complement

C4 Complement

Brown clotted serum, gel barrier or lithium heparin

TestC4 Complement
Common AbbreviationsC4, C4C
Tube typeBrown clotted serum, gel barrier or lithium heparin
Clinical IndicationActivation or consumption of complement occurs in a number of disorders, particularly those involving immune complex deposition e.g. SLE, mixed cryoglobulinaemia and some forms of vasculitis, however this may be compensated for in part by the synthesis of acute phase reactants. C3 comprises about 30% of the total plasma concentration of complement components and is consumed by activation of both the classical and alternative pathways. C4 levels fall only as a consequence of classical pathway activation, therefore if hypocomplementemia is present, measurement of both C3 and C4 can determine whether the classical or alternative pathway has been activated.
Specimen TypeBlood
Sample typeSerum
Minimum Volume0.5mL If requesting more than 10 tests please send an additional brown clotted serum sample.
Special PrecautionsNo special requirements
Stability2 days at 15-25°C and 8 Days at 2-8°C
Turnaround TimeInpatient: 4 days Outpatient/ GP: 4 days
Reference Interval0.1 - 0.4 g/L
LimitationsThe assay should not be performed on grossly haemolysed or lipaemic samples. Samples with extremely abnormal optical characteristics, especially turbidity may produce atypical results.
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