Hepatitis B surface antigen quantitative od (optical density) normal value is usually less than 0.5ng/ml. If the quantitative value of Hepatitis B surface antigen is lower than 0.5ng/ml and the qualitative test of Hepatitis B surface antigen is negative, it means that the body is not infected with Hepatitis B virus; if the quantitative value of Hepatitis B surface antigen is higher than 0.5ng/ml and the qualitative test of Hepatitis B surface antigen is positive, it means that the body is infected with Hepatitis B virus. Since there is no way to get rid of hepatitis B virus by medication, once infected with hepatitis B virus, patients must take medication as soon as possible to control the continuous replication of hepatitis B virus, which will lead to cirrhosis of the liver, or even liver cancer and other serious consequences. The danger of hepatitis B virus is not to be underestimated, for this disease, there is no effective medicine, the best way is to diagnose and treat it as early as possible.