A positive antigen is a certain test, if the test is performed from the blood, it means that antigens can be found from the blood, there are different types of specific antigens, and the complete name of the test should be clarified. If the result is positive for surface antigen of hepatitis B, it means that it is a person with hepatitis B. The surface antigen of hepatitis B will only appear if the hepatitis B virus infects the body and carries out a large number of reproduction. If the result is positive for the antigen of hepatitis C, it also indicates a person with hepatitis C. If the antigen is positive for other antigens, it also indicates the presence of a microbial infection of antigenic origin. Positive antigens are usually associated with a corresponding infection, and the tests performed in the clinic are also performed for the antigen of the microorganism. Self-cells sometimes also expose antigens for their own immune system to attack, and this aspect of the test is less often used in clinical practice, and is mostly determined by tests for autoantibodies.