Question

ELISA is used to detect viruses where the key reagent is

• A. alkaline phosphatase
• B. catalase
• C. DNA probe
• D. RNase.

Answer 1

Answer: (A)

alkaline phosphatase

Answer 2

ELISA (enzyme linked immunosorbent assay) screening test is the initial test to diagnose AIDS. The test works by detecting anitibodies/substances or protein which are produced in the blood when virus is present. Alkaline phosphatase and peroxidases are commonly I used enzymes as key reagent to perform the ELISA test. These enzymes are used to provide antibody- antigen complex in a specialised ELISA plate or tray. In ELISA test for detecting a particular antigen, its antibody is buffered and a drop of serum (supernatant of centrifuged blood) poured over it. If the latter contains antigen, it will produce antigen-antibody complex. A second enzyme labelled antibody is added. It forms enzyme-antigen-antibody complex, if the antigen is present. Substrate is now added. It produces a stain if the antigen is present.