Hepatitis B virus level test can be used to determine whether the body is infected with hepatitis B virus, the infectiousness of the infectiousness, and to detect the effectiveness of antiviral therapy. 1. Whether the body is infected with hepatitis B virus. When the human body is infected with hepatitis B virus, through the hepatitis B virus level test can clarify the level of hepatitis B virus, if there is a positive result, it suggests that it is infected with hepatitis B virus. 2. Infectious size. When the level of hepatitis B virus is high, it suggests that the virus replication in the body is more active and infectious. 3. Detect antiviral efficacy. If after active antiviral treatment, the therapeutic effect is good, the level of hepatitis B virus will decrease. Therefore, it can be judged according to the doctor’s instruction combined with the hepatitis B virus level test.