For individuals with hepatitis B, Entecavir is undoubtedly a familiar medication. It is recommended as a first-line antiviral drug in hepatitis B prevention and treatment guidelines. However, patients who take Entecavir long-term must undergo a high-sensitivity viral load test (with a detection limit of 10 or 20 IU/mL), especially those whose routine viral tests show no detectable virus. This is crucial to guard against low-level viremia. Theoretically, taking Entecavir for over one year should lead to the clearance of hepatitis B virus. Low-level viremia refers to a condition where, after more than one year of antiviral treatment, the viral load in the blood is below 2,000 IU/mL, but the virus is still detectable by high-sensitivity testing. This indicates that the hepatitis B virus continues to replicate at a low level, leading to ongoing liver damage.

For hepatitis B patients, once low-level viremia occurs, the risk of drug resistance increases, and the likelihood of disease progression to cirrhosis or liver cancer rises significantly. Therefore, patients on long-term Entecavir therapy must undergo high-sensitivity viral load testing to rule out the risk of low-level viremia!