In normal people who are not infected with hepatitis B virus, there is no hepatitis B virus in the body, and the measurement of hepatitis B DNA is 0 and cannot be measured. But patients with hepatitis B, through the test can determine the replication of the virus, the amount is higher may also be more infectious. In general, for hepatitis B unit copy value patients hepatitis B DNA quantification is generally small 100 is almost undetectable virus, less infectious. If the amount of virus is more than 100 can be detected, each hospital check with the reagent method may be slightly different, some can only check to 1000 level, but most of the public tertiary hospitals can determine to 100, if the hepatitis B patient this value is less than 100, indicating that the amount of virus is very small, normal people will not be checked to the hepatitis B virus.