Which diagnostic test is commonly used to confirm AIDS diagnosis?

The confirmation of an AIDS diagnosis primarily relies on the CD4 T-cell count. When the CD4 T-cell count falls below 200 cells/mm³, it is indicative of a severely weakened immune system, which characterizes the progression from HIV infection to AIDS. This specific threshold is a critical marker that helps healthcare providers assess the state of a patient's immune system, guiding treatment and care decisions.

In contrast, the other tests listed do not provide direct confirmation of AIDS. A blood glucose test measures glucose levels and is primarily used to manage diabetes rather than diagnose AIDS. A complete blood count provides general information about various blood cells but does not specifically focus on immune function related to HIV infection. Liver function tests assess liver health, which may be impacted by various conditions including some complications of HIV treatment, but they do not directly correspond to the diagnosis of AIDS. Therefore, the CD4 T-cell count is the appropriate test to confirm an AIDS diagnosis due to its direct relationship with the immune status of individuals infected with HIV.