Hepatitis B patients tested for hepatitis B deoxyribonucleic acid below the lower limit of detection refers to a blood test for quantification of hepatitis B virus DNA, which is deoxyribonucleic acid. Below the lower limit of detection depends on how much the lower limit of detection is, the common test implemented is 10^3, below 10^3 the hepatitis B virus DNA can still be present in the blood, but it is no longer detectable. It is possible to detect it only with a high sensitivity test, which is not used to rule out hepatitis B alone, but only to monitor the amount of hepatitis B virus in hepatitis B patients. When antiviral therapy with oral nucleoside analogues is effective, the viral load should be consistently below the lower limit of detection, and once it can be detected, it is suspected that the antiviral drugs are not being taken regularly or that the virus is resistant.