Tests for Virus infection:

–PCR Viral genome can be applied. Even allows quantification of virus. But due to high sensitivity of PCR can rarely have false negatives particularly where concentration of virus very low (as where virus is integrated into cell). HIV virus concentration decreases after infection and gets so low that often hard to detect even with PCR.

PCR can also result in false positives.

–-syncytia formation

–ELISA: Viral antigens are absorbed onto a solid phase and the patient’s serum is added. Unbound antibody is washed away and then enzyme-conjugated goat antihuman immunoglobulin is added. After washing excess reagent away, the substrate for the enzyme is added.

–Western Blot Assay: HIV proteins are separated by electrophoresis and then transferred to a nitrocellulose membrane. Patient’s serum is added to the nitrocellulose and allowed to react. Radiolabeled goat antihuman immunoglobuline is then added. The presence of radioactive bands corresponding to the molecular weight of the antigens indicates the presence in the patient of antibody to HIV.