Complement, Total, C3, and C4



Total hemolytic complement, CH50, CH100.


To detect inborn complement deficiency, evaluate immune diseases related to complement activity, and follow up on a patient’s response to therapy such as treatment for rheumatoid arthritis and systemic lupus erythematosus (SLE) in which complement is consumed at an increased rate.

Patient Preparation

There are no food, fluid, activity, or medication restrictions unless by medical direction.

Normal Findings

Method: Immunoturbidimetric for C3 and C4.

Total Complement (CH50)
Complement Total (CH50) Units/mLMethod
23–60Liposome Immunoassay
60–140Enzyme Immunoassay
100–300Quantitative Hemolysis (Classical method)

AgeConventional UnitsSI Units (Conventional Units × 0.01)
Newborn57–116 mg/dL0.57–1.16 g/L
6 mo–adult74–166 mg/dL0.74–1.66 g/L
Adult83–200 mg/dL0.83–2 g/L

AgeConventional UnitsSI Units (Conventional Units × 0.01)
Newborn10–31 mg/dL0.1–0.31 g/L
6 mo–6 yr15–52 mg/dL0.15–0.52 g/L
7–12 yr19–40 mg/dL0.19–0.4 g/L
13–15 yr19–57 mg/dL0.19–0.57 g/L
16–18 yr19–42 mg/dL0.19–0.42 g/L
Adult12–36 mg/dL0.12–0.36 g/L

Critical Findings and Potential Interventions


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