Most common viral antigen used for diagnosis of HIv
High-Yield Explanation
Ref Robbins 7/e p246; 9/e p245 p24 antigen assay: It is available only as a blood test. It detects the HIV antigen called p24 plus antibodies to HIV-1 and HIV-2. ... The level of p24 antigenand the amount of virus (viral load) increase significantly soon after initial infection. Testing for p24 allows for detection of early infections, before HIV antibody is produced