S-HBs Ag non-reactive is a medical term commonly used in laboratory tests for hepatitis B. S-HBs Ag refers to the hepatitis B surface antigen, which is a protein part of the hepatitis B virus and is usually present in the blood of a person infected with the hepatitis B virus. The term "non-reactive" means that the test did not detect the presence of this antigen in the blood sample. This means that the person is most likely not infected with the hepatitis B virus. However, it should be noted that the test can also be negative in the early stages of infection when the virus is not yet concentrated enough for the test to detect it. Therefore, it is important that all test results are interpreted taking into account clinical information and other laboratory tests.