Hepatitis B 2.5 positivity refers to positive surface and core antibodies to hepatitis B respectively. It may be that the patient has been infected and cured of the hepatitis B virus and has developed protective antibodies. It is also possible that a mutation has occurred. Hepatitis B surface antibody is a kind of protective antibody in the body, which can help the body to resist the attack of hepatitis B virus. The higher the titer, the stronger the body’s ability to fight off the hepatitis B virus. Positive hepatitis B core antibodies often indicate that the patient is in a period of hepatitis B virus infection or has been infected with the hepatitis B virus. In a few cases, when the hepatitis B virus is mutated, the hepatitis B surface antibody and the hepatitis B core antibody are positive at the same time, which may also be infected with the mutated hepatitis B virus. In this case, it is necessary to check the hepatitis B viral load in the body, and if infection with the mutated virus is found, prompt treatment is required. If patients with hepatitis B are positive for both surface and core antibodies, they should go to the hospital in time to have the cause clarified and targeted treatment.