A young male comes with 8 wks history of fever, anorexia, lymphadenopathy and weight loss. He also gives history of unprotected sexual intercourse 8 wks ago suspected as an AIDS patient earliest test which is appropriate is:
a. The simplest of the direct detection tests is the p24 antigen capture assay. This is an EIA-type assay in which the solid phase consists of antibodies to the p24 antigen of HIV.
b. Overall, ~30% of individuals with untreated HIV infection have detectable levels of free p24 antigen. This increases to ~50% when samples are treated with a weak acid to dissociate antigen-antibody complexes. Throughout the course of HIV infection, an equilibrium exists between p24 antigen and anti-p24 antibodies.
c. The p24 antigen capture assay has its greatest use as a screening test for HIV infection in patients suspected of having the acute HIV syndrome, as high levels of p24 antigen are present prior to the development of antibodies.