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.

Immunotherapy is increasingly becoming standard therapy in cancer, with technology, such as checkpoint inhibitors and cell therapy, raising the efficacy bar in many forms of the disease. But the ...

A complement blood test checks for autoimmune diseases or other issues with your immune system. Your doctor might test you if you have a family history of certain conditions, such as rheumatoid ...