Total complement is serum total complement activity, also known as CH50 measurement, total complement is high in a variety of acute inflammation, tissue injury, malignant tumors, etc.; also can be seen in the late stage of pregnancy, etc.. Total complement can reflect the activity of the traditional pathway activation of complement, commonly used in clinical hemolysis method, the total complement is high in a variety of acute inflammation, tissue injury, malignant tumors, such as typhoid fever, tuberculosis, rheumatic fever, urticaria, etc., especially rheumatoid immune disease, the total complement is high is usually the most likely to be the disease, but it is necessary to combine with the clinical symptoms and other auxiliary examination for diagnosis. In addition, an increase in total complement can also be seen in the second trimester of pregnancy, which is a physiologic increase. It is recommended that patients with elevated total complement tests should seek prompt medical attention for early treatment and diagnosis.