7525 C4, (Complement), Serum

Specimen Type Specimen Stability Reference Range
Serum 7 Days, Refrigerated
72 Hours, Ambient
30 Days, Frozen
16 - 47 mg/dL

Specimen Requirements

Specimen Type: Serum
Container: 1 Serum Separator Tube (SST)
Temperature: Refrigerated
Preferred Vol: 1.00 mL
Min Vol: 0.50 mL




Monday - Saturday

Turn-Around Time



Overnight fasting preferred.

Clinical Utility

The complement system can be activated via the classical and the alternative route. A decrease in C4 is common, but complete absence is rare. A lowered concentration or the complete absence of C4 occurs in immunocomplex diseases, systemic lupus erythematosus (SLE) autoimmune thyroditis and juvenile dermatomyositis. Low C4 with high dsDNA autoantibodies confirms the diagnosis of SLE and may help monitor activity.

CPT Codes


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