C3 complement component

A C3 complement blood test measures the levels of a specific type of protein in your blood (C3 proteins). As part of your immune system, C3 proteins destroy microbes (germs) that can make you sick. Sometimes, C3 proteins launch an attack against healthy cells by mistake. The results of this blood test give your healthcare provider information about how your immune system is working. By measuring the amount of C3 proteins, your healthcare provider can diagnose infection, disease, immune deficiency, and other health conditions, like autoimmune disorders. This test also helps your healthcare provider monitor treatment for autoimmune disease.