For a brief introduction and guide to abbreviations, see Laboratory Tests: General Remarks.
Analyte [material]
Complement, total (CH50), C3, and C4 [S]
Reference range, target level, or decision threshold
CH50 (total complement activity): 90-150 U/mL!!!
C3: 0.55-1.2 g/L!!!
C4: 0.2-0.5 g/L!!!
Interpretation of results
↑ Infections
↓ Congenital complement deficiency, liver diseases, complement consumption (activation by circulating immune complexes), SLE