The normal values of the experiments used may be different due to the different testing organizations or reagents, but in general the normal value of Complement C4 is between 0.1 and 0.4 g/L, and 0.14 g/L is a normal level. Complement C4 is a kind of globulin synthesized by the liver, mostly found in human plasma, mainly reflecting whether the human immune system is abnormal. When liver disease or autoimmune disease exists, the level of Complement C4 may change. Complement C4 measured at 0.14 g/L is at normal level. However, since complement C4 cannot be used as a specific indicator for a particular disease, it cannot be used to determine whether there is a problem based solely on whether complement C4 is normal or not, but can only be used as an auxiliary test to determine the severity of the disease in question.