Preferred Specimen(s) 0.5 mL Serum
Instruction
- Overnight fasting is preferred.
- Serum should be separated immediately from clot.
Transport Container Plastic screw cap vial
Transport Temperature Refrigerated 1 week
Reject Criteria Grossly hemolysed specimen
Methodology Nephelometry
Clinical Significance: C3 is the most abundant complement protein and is critical to activation of both the classical and alternative pathways. C3 is an acute phase reactant. Decreased concentrations are observed in patients with systemic lupus erythematosus (SLE), endocarditis, and disseminated intravascular coagulation (DIC). Congenital deficiency of C3 places such patients at high risk for recurrent bacteremia.