HBV DNA testing is a method to detect whether hepatitis B virus exists in the blood and plays a role in evaluating the treatment effect of hepatitis B. The blood of normal people does not contain hepatitis B virus, and a positive result of HBV DNA testing indicates infection with hepatitis B virus. Information such as the number of hepatitis B viruses and whether they are contagious can be obtained, so HBV DNA testing is very important. Hepatitis B virus should not exist in the blood of normal people, so normal test results should be negative or marked as below the detection limit on the report. Any positive marking or numerical value indicates infection with hepatitis B virus, which is an abnormal result. HBV DNA testing is becoming more common in hepatitis B testing, indicating that HBV DNA testing plays an increasingly important role in hepatitis B testing. This is because HBV DNA testing plays a very important role in confirming hepatitis B and evaluating the treatment effect of hepatitis B, mainly manifested in the following seven aspects: 1. Understand the number of hepatitis B viruses present in the body; 2. Whether hepatitis B virus replicates; 3. Whether hepatitis B is contagious and how contagious it is; 4. Whether it is necessary to take medication; 5. Whether the abnormal change in liver function is caused by hepatitis B virus; 6. Determine which antiviral drug is suitable for the patient; 7. Judge the efficacy of drug treatment.