Early detection: closing the window

Summary:
It could reduce the risk of HIV infection by blood transmission by sifting diagnostic test to HIV antibody in human blood. At present the main sifting diagnostic test for HIV antibody in human blood is the 3rd generation of HIV ELISA test. Different from the 1st and 2nd generation HIV ELISA test, the method of 3rd generation of HIV ELISA test is double antigen sandwich, which could detect all kinds of antibody of HIV and improves its sensitivity and specificity as well. it is the main diagnostic ELISA test worldwide now. At present, it is applied in most of routine blood sifting tests.
 
HIV P24 antigen may show up at the beginning of HIV infection when the HIV antibody could not be detected.

The method of 4th generation of HIV ELISA test is that HIV antigen and Antigen coat the vector simultaneously, and detect the HIV P24 and HIV antibody in the sample at the same time. So, it could be used for detection for the samples of window period which shows positive in HIV P24 antigen tests but is not transformed into HIV infection.