Complement component 3 (C3)

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

Blood test

Overview

Risks

Results

Complement component 3 (C3)

Alternative Names:

C3
What the risks are:

excessive bleeding
fainting or feeling light-headed
hematoma (blood accumulating under the skin)
infection (a slight risk any time the skin is broken)
multiple punctures to locate veins

Special considerations:

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The complement cascade can be started in several ways, especially by antigen-antibody complexes. The end-product of the cascade is the "membrane attack unit" (also called terminal complement component), which creates holes in the membranes of attacking bacteria, thereby killing them.

CH50 and CH100 are tests for the activity of the complement system. There are also a number of side products of the complement cascade that attract white blood cells and increase the efficiency of certain types of white blood cells to engulf and destroy bacteria.

Some bacteria don't need specific antibodies to be present for the complement system to be activated. C3, one of the major components of the complement cascade, attaches to and kills these bacteria directly.

Typically, other tests that are more specific for the suspected disease are performed first.