ELISA test

Question 1

What does ELISA stand for

Answer 1

Enzyme-linked immunosorbent assay

Question 2

What does the ELISA test do?

Answer 2

Test to see if a patient has a certain antibody or antigen

Question 3

What is direct ELISA?

Answer 3

Uses a single antibody

Question 4

What is an indirect ELISA?

Answer 4

Uses two different antibodies

Question 5

Describe direct ELISA

Answer 5

• an enzyme is attached to antibodies
  -when this enzyme reacts with a certain substrate a coloured product is formed

Question 6

What does a colour change mean in the direct ELISA test ?

Answer 6

It shows that the antigen or antibody of interest is present in the sample being tested (eg blood plasma)

Question 7

Testing for HIV with the ELISA test (indirect)

Answer 7

-HIV antigen is bound to the bottom of the well (immobilised)
-patients blood plasma added
-antibody specific to HIV antigen binds
-Non-specific antibodies remain in solution
-well washed to remove unbound antibodies
-Second antibody was specific enzyme attached binds to HIV specific antibody
-well washed to remove unbound antibodies
-solution containing specific substrate added
-colour change = positive