Complement

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Complement assay; Complement proteins

• 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

Complement is a group of proteins involved in immunological and inflammatory responses. There are 9 major components of complement labeled C1 through C9.

The "complement cascade" is a series of reactions that take place in the blood. The cascade can be started in several ways, especially by antigen-antibody complexes. The end product of the cascade is called the "membrane attack unit" (also called the terminal complement component). This attack unit creates holes in the membranes of attacking bacteria, killing them.

CH50 or CH100 are tests for the activity of the complement system. Typically, other tests that are more specific for the suspected disease are performed first.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Review Date: 04/20/2005
Reviewed By: Stanford Peng, M.D., Ph.D., Division of Rheumatology, Washington University School of Medicine, St. Louis, MO. Review provided by VeriMed Healthcare Network.