Generally, a weakly positive hepatitis B surface antigen indicates infection with hepatitis B, but false positives are also possible. Weak positive hepatitis B surface antigen usually occurs in the following situations: 1. Acute hepatitis B recovery: patients infected with hepatitis B after immune clearance occurs, the condition naturally improves, in the recovery period, can appear hepatitis B surface antigen weak positive. 2. Chronic hepatitis B: Virus carriers with chronic HBV infection may also be weakly positive if the virus is not very active and the titer of surface antigen is not very high. 3. Early stage of acute hepatitis B virus infection: the amount of virus in the early stage of hepatitis B virus infection is not particularly high, and the level of surface antigen is not very high, and the test result may also reflect weak positivity. 4. False positive: Hepatitis B surface antigen is weakly positive, which may be caused by low sensitivity of reagents. If hepatitis B surface antigen is weakly positive, it is also necessary to check the quantification of hepatitis B virus, liver ultrasound, liver function and other tests to make a clear diagnosis.