Why is anti-HIV-1 IgG screened instead of the virus itself?

Anti-HIV-1 IgG is screened instead of the virus itself because antibodies typically persist longer in the body than the virus, making them more reliable indicators of infection. This approach allows for earlier detection, as antibodies can be present even when the viral load is low or undetectable. Additionally, testing for antibodies is often simpler, faster, and more cost-effective than directly measuring viral presence. Thus, antibody screening is a practical method for diagnosing HIV infection.