Print this article
Share this page:
Also known as: C1; C1q; C2; C3; C4; Total Complement; CH50; CH100; Total Haemolytic Complement Activity; C1 esterase inhibitor
Formal name: Complement Activity; Complement Component C3; Complement Component C4
Related tests: ESR; CRP; RF; ANA; Autoantibodies

At a Glance

Why Get Tested?

To determine whether complement system proteins are contributing to increased infections or autoimmune disease. To monitor the activity of certain autoimmune diseases. To help diagnose hereditary angioedema.

When to Get Tested?

When you have recurrent (usually bacterial) infections, unexplained episodes of swelling, or symptoms related to certain autoimmune disorders. Periodically to help monitor a known long term disease such as systemic lupus, that affects the complement system.

Sample Required?

A blood sample taken from a vein in your arm

Test Preparation Needed?