Which test is considered confirmatory for diagnosing AIDS?

Western blot is considered the confirmatory test for diagnosing AIDS due to its high specificity. While initial screenings for HIV infection often utilize tests like the ELISA (Enzyme-Linked Immunosorbent Assay) or rapid antibody tests, these methods can sometimes yield false-positive results. The Western blot test detects specific proteins that indicate the presence of HIV, confirming a diagnosis when results from preliminary tests are positive.

In contrast, while the ELISA can detect antibodies against HIV effectively, it is used primarily as an initial screening tool. The rapid antibody test is designed for quick results but, similar to the ELISA, is not definitive on its own. The CD4 count, which measures the immune system's health, helps in determining the stage of HIV infection and the need for treatment, but it does not confirm the presence of the virus itself. Thus, the Western blot remains the gold standard in confirming an HIV diagnosis and subsequently, the progression to AIDS.