The quantitative HIV antibody test is one of the most commonly used methods to detect whether a patient is infected with HIV in China and is the gold standard for the diagnosis of HIV infection, usually after a two-step screening test and a confirmatory test for patient identification. The initial screening test is usually performed using ELISA, chemiluminescence or immunofluorescence, and the sensitivity can reach more than 99%. If the initial screening patient is positive, a confirmatory test should also be performed by protein blotting assay. If the confirmatory test is negative, the patient is not infected with HIV. If the confirmatory test is also positive, the patient is confirmed to be infected with HIV. The patient’s CD4+ T-lymphocyte count and HIV-RNA should then be further checked and the next step in treatment should be taken.