Your complement system consists of a group of important proteins in your bloodstream. These proteins help your immune system fight off harmful invaders, such as bacteria, and other foreign substances.

It was called ‘complement’ because it aided the antibacterial activity of antibodies. However, it is now known that the complement system can be activated early in an infection without the presence of ...

The complement proteins that circulate in our blood are an important part of our immune system. They help identify bacteria, viruses and other harmful organisms, making it easier for our white blood ...

A complement blood test measures how well complement proteins in your blood support immune defense. The complement system helps antibodies fight germs and clear foreign substances. Complement testing ...