Precipitation and Agglutination Textbook Questions

Question 1

In a precipitation reaction, how can the ideal antibody be characterized?

a. Low affinity and low avidity
b. High affinity and low avidity
c. High affinity and high avidity
d. Low affinity and high avidity

Answer 1

c. High affinity and high avidity

Question 2

Precipitation differs from agglutination in which way?

a. Precipitation can only be measured by an automated instrument.
b. Precipitation occurs with univalent antigen, whereas agglutination requires multivalent antigen.
c. Precipitation does not readily occur because few antibodies can form aggregates with antigen.
d. Precipitation involves a soluble antigen, whereas agglutination involves a particulate antigen.

Answer 2

d. Precipitation involves a soluble antigen, whereas agglutination involves a particulate antigen.

Question 3

When soluble antigens diffuse in a gel that contains antibody, in which zone does optimal precipitation occur?

a. Prozone
b. Zone of equivalence
c. Postzone
d. Prezone

Answer 3

c. Postzone

Question 4

Which of the following statements applies to rate nephelometry?

a. Readings are taken before equivalence is reached.
b. It is more sensitive than immunoturbidimetry.
c. Measurements are time dependent.
d. All of the above apply.

Answer 4

a. Readings are taken before equivalence is reached.

Question 5

Which of the following is characteristic of the endpoint method of RID?

a. Readings are taken before equivalence.
b. The antigen concentration is directly in proportion to the square of the ring diameter.
c. The ring diameter is plotted against the log of the concentration.
d. It is primarily a qualitative rather than a quantitative method.

Answer 5

b. The antigen concentration is directly in proportion to the square of the ring diameter.

Question 6

In which zone might an antibody-screening test be false negative?

a. Prozone
b. Zone of equivalence
c. Postzone
d. None of the above

Answer 6

a. Prozone

Question 7

How does immunoturbidimetry differ from nephelometry?

a. Immunoturbidimetry measures the increase in light after it passes through a solution.
b. Nephelometry measures light that is scattered at an angle.
c. Immunoturbidimetry deals with univalent antigens only.
d. Nephelometry is not affected by large particles falling out of solution.

Answer 7

b. Nephelometry measures light that is scattered at an angle.

Question 8

Which of the following refers to the force of attraction between an antibody and a single antigenic determinant?

a. Affinity
b. Avidity
c. Van der Waals attraction
d. Covalence

Answer 8

a. Affinity

Question 9

If crossed lines result in an Ouchterlony immunodiffusion reaction with antigens 1 and 2, what does this indicate?

a. Antigens 1 and 2 are identical.
b. Antigen 2 is simpler than antigen 1.
c. Antigen 2 is more complex than antigen 1.
d. The two antigens are unrelated.

Answer 9

d. The two antigens are unrelated.

Question 10

Which technique represents a single-diffusion reaction?

a. Radial immunodiffusion
b. Ouchterlony diffusion
c. Counter immunoelectrophoresis
d. Immunofixation electrophoresis

Answer 10

a. Radial immunodiffusion

Question 11

Which best describes the law of mass action?

a. Once antigen–antibody binding takes place, it is irreversible.
b. The equilibrium constant depends only on the forward reaction.
c. The equilibrium constant is related to the strength of antigen–antibody binding.
d. If an antibody has a high avidity, it will dissociate from antigen easily.

Answer 11

c. The equilibrium constant is related to the strength of antigen–antibody binding.

Question 12

Agglutination of dyed bacterial cells represents which type of reaction?

a. Direct agglutination
b. Passive agglutination
c. Reverse passive agglutination
d. Agglutination inhibition

Answer 12

a. Direct agglutination

Question 13

If a single IgM molecule can bind many more antigens than a molecule of IgG, which of the following is higher?

a. Affinity
b. Initial force of attraction
c. Avidity
d. Initial sensitization

Answer 13

c. Avidity

Question 14

Agglutination inhibition could best be used for which of the following types of antigens?

a. Large cellular antigens, such as erythrocytes
b. Soluble haptens
c. Bacterial cells
d. Coated latex particles

Answer 14

b. Soluble haptens

Question 15

Which of the following correctly describes reverse passive agglutination?

a. It is a negative test.
b. It can be used to detect autoantibodies.
c. It is used for identification of antigens.
d. It is used to detect sensitization of RBCs.

Answer 15

c. It is used for identification of antigens.

Question 16

Reactions involving IgG may need to be enhanced for which reason?

a. IgG is only active at 25°C.
b. IgG may be too small to produce lattice formation.
c. IgG has only one antigen-binding site.
d. IgG is only able to produce visible precipitation reactions.

Answer 16

b. IgG may be too small to produce lattice formation.

Question 17

For which of the following tests is a lack of agglutination a positive reaction?

a. Hemagglutination
b. Passive agglutination
c. Reverse passive agglutination
d. Agglutination inhibition

Answer 17

d. Agglutination inhibition

Question 18

Typing of RBCs with reagent antiserum represents which type of reaction?

a. Direct hemagglutination
b. Passive hemagglutination
c. Hemagglutination inhibition
d. Reverse passive hemagglutination

Answer 18

a. Direct hemagglutination