Complement-3 or the C3 blood test monitors the activity of a certain protein of our immune system. It is a part of the complement system which is constituted by a group of freely moving proteins in the bloodstream. Altogether there are nine such proteins identified and they are named in the order C1 to C9. The complement system guards our body against infections, dead cells and foreign materials. In rare cases, people may inherit deficiency of some complement proteins. Such people are prone to autoimmune disorders or certain infections. The c3 protein plays a pivotal role in the development of inflammation.
