Blood tests can detect AIDS. If AIDS is suspected, blood will be drawn first to check for HIV antibodies, and if HIV antibodies are positive, it can be used as a primary screening test, and then a confirmatory test will be performed. Blood tests related to HIV are also required, such as CD4+ T-lymphocytes, and a decrease in CD4+ T-lymphocytes is a typical sign of AIDS. CD4+ T lymphocytes are a typical manifestation of AIDS because after HIV enters the body, it mainly targets the most important CD4+ T lymphocytes and damages the immune status of the body. Another test is the HIV nucleic acid test. The HIV nucleic acid test can check that the virus will increase rapidly in the blood after the body is infected with HIV, so the viral load can be determined by the HIV nucleic acid test.