Final answer:
AIDS is diagnosed using serological tests like ELISA for initial screening, followed by confirmatory tests such as Western blot or PCR to detect HIV antibodies or viral presence definitively.
Step-by-step explanation:
Laboratory tests used to confirm the diagnosis of AIDS include serological tests for antibodies and/or HIV antigens, and nucleic acid tests (NATs). The initial diagnosis is often performed using an indirect ELISA that detects antibodies specific to HIV.
However, to account for possible false positives due to cross-reactivity with other antibodies, a confirmatory test—either Western blot or polymerase chain reaction (PCR)—is necessary. Western blotting provides a visual representation of HIV antibodies binding to viral proteins, offering confirmation of infection. Nucleic acid tests like RT-PCR can detect presence of the virus itself and are used to determine viral load, which is essential for staging and treatment monitoring.