Immunochemical Techniques

Question 1

1. What does a strong signal in a microtiter well–based
   competitive enzyme immunoassay (EIA) for thyroxine
   signify?

a. A low concentration of thyroxine in the sample
b. A high concentration of thyroxine in the sample
c. Enzyme substrate not added to the well
d. Enzyme inhibitor present in the sample
e. Bound antibody has detached from the surface of the
well

Answer 1

d. Enzyme inhibitor present in the sample

Question 2

2. What does a very weak signal in a microtiter well–based
   sandwich EIA for thyroid-stimulating hormone (TSH)
   signify?

a. A low concentration of TSH in the sample
b. A high concentration of TSH in the sample
c. A hook effect
d. Effective competition between the conjugate and the
TSH for capture antibody
e. Capture antibody saturated with TSH:conjugate
complexes

Answer 2

a. A low concentration of TSH in the sample

Question 3

3. The energy of interaction of a single antibody-combining site and its corresponding epitope on the antigen is
   referred to as:

a. sensitivity.
b. specificity.
c. immunogenicity.
d. affinity.

Answer 3

d. affinity.

Question 4

4. Which one of the following immunochemical assays
   requires separation of the free label from the bound
   labeled substance?

a. Enzyme-multiplied immunoassay technique (EMIT)
b. Enzyme-linked immunosorbent assay (ELISA)
c. Cloned enzyme donor immunoassay (CEDIA)
d. Luminescent oxygen channeling immunoassay (LOCI)
e. Fluorescence polarization immunoassay (FPIA)

Answer 4

e. Fluorescence polarization immunoassay (FPIA)

Question 5

5. The addition of a linear polymer such as polyethylene glycol to a mixture of antigen and antibody
   causes____________ in the rate of immune complex formation and precipitation.

a. a decrease
b. an increase
c. no change

Answer 5

b. an increase

Question 6

6. Transferring electrophoretically separated proteins into a strip of nylon membrane by electroblotting is the second step in:

a. radial immunodiffusion.
b. enzyme-linked immunosorbent assay.
c. Western blotting.
d. immunofixation.
e. crossed immunoelectrophoresis

Answer 6

c. Western blotting.

Question 7

7. In a two-site antibody-based sandwich immunoassay,
   the presence of human anti-mouse antibodies produces
   a false-negative result by:

a. binding a mouse immunoglobulin capture antibody
and the mouse immunoglobulin conjugate to form a
bridge.
b. mimicking the specific analyte being assessed.
c. binding to the mouse monoclonal capture antibody
reagents.
d. reacting with one of the assay reagents to prevent
formation of the sandwich.

Answer 7

d. reacting with one of the assay reagents to prevent
formation of the sandwich

Question 8

8. Which one of the following immunoassay procedures
   does not involve the coating of a solid phase with antibody or antigen?

a. Enzyme-multiplied immunoassay technique (EMIT)
b. Luminescent oxygen channeling immunoassay (LOCI)
c. Enzyme-linked immunosorbent assay (ELISA)
d. Particle-enhanced turbidimetric inhibition immunoassay (PETINIA)
e. Bio-barcode immunoassay

Answer 8

b. Luminescent oxygen channeling immunoassay (LOCI)

Question 9

9. The immunoglobulin most often used in immunochemical assays is:

a. IgG.
b. IgA.
c. IgM.
d. IgE

Answer 9

a. IgG.

Question 10

10. Which one of the following statements is false?

a. Dyed-latex microparticles are effective labels in simplified immunoassays because they are visible to the
naked eye
b. Binding of an antigen to an antibody involves van der
Waals-London dipole-dipole interaction
c. Addition of polymers to an antigen antibody reaction
increases the rate of immune complex growth
d. The functional sensitivity of an immunoassay is the
lowest concentration that can be measured with a
within-assay coefficient of variation of 20%
e. Fluorescence resonance energy transfer from donor
to acceptor dye is distance dependent

Answer 10

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