radioimmunoassay (RIA)

Question 1

RIA are similar to ELISA but use

Answer 1

radiolabeled antibodies rather than the enzyme-linked antibodies

Question 2

results are based on

Answer 2

presence of target protein or antibodies by measuring the amount of radioactivity (instead of color change in ELISA)

Question 3

RIA real life use is in

Answer 3

measuring amounts of hormones or drugs in a patient’s sera

Question 4

step 1:

Answer 4

a known amount of radiolabeled antigen is incubated with a known amount of antibody that is specific to antigen
*ex: insulin is usually synthesize with I-labeled tyrosines)

Question 5

step 2:

Answer 5

the insulin antibody complexes are isolated

Question 6

step 3:

Answer 6

total amount of radioactivity is measured

Question 7

step 4:

Answer 7

unlabeled (cold) insulin is mixed into solution in increasing amount
cold insulin competes with labeled (hot) insulin for the antibody
competition assay formulate standard curve

Question 8

as more cold insulin is added, the

Answer 8

less total radioactivity is recovered and measured

Question 9

step 5:

Answer 9

steps 1-3 are repeated using patient serum instead of cold insulin thus the standard curve can be used to extrapolate the amount of insulin in patient’s serum

Question 10

the concentration of the radiolabeled proteins are determined by counting the

Answer 10

gamma emission