Deck 10: Precipitation and Agglutination Reactions

Question 1

When carrier particles are coated with an antigen that is not normally found on them,this is known as:

A) direct agglutination.
B) passive agglutination.
C) reverse passive agglutination.
D) hemagglutination.

Answer 1

passive agglutination.

Question 2

If the concentration of free antibody (Ab)= 3 mol/L,the concentration of free antigen (Ag)= 2 mol/L,and the concentration of antigen-antibody complex = 6 mol/L,then the equilibrium constant K equals:

A) 1.
B) 2.
C) 4.
D) 9.

Answer 2

1.

Question 3

When a patient's red blood cells combine with anti-A typing serum to produce a positive result,this reaction is known as:

A) passive agglutination.
B) reverse passive agglutination.
C) hemagglutination.
D) flocculation.

Answer 3

hemagglutination.

Question 4

The production of insoluble complexes that absorb or scatter light but are too small to see directly is called:

A) precipitation.
B) agglutination.
C) equivalence.
D) sensitization.

Question 5

The measurement of light scattered at an angle by the antigen-antibody complexes in a solution is called:

A) turbidimetry.
B) nephelometry.
C) agglutination.
D) equivalency.

Question 6

Based on the following equilibrium constants,which assay would have the best sensitivity?

A) K = 1
B) K = 2
C) K = 4
D) K = 9

Question 7

A radial immunodiffusion test is run for 72 hours.The concentration of the antigen is then calculated using the:

A) radius of the precipitation ring.
B) diameter of the precipitation ring.
C) square of the diameter of the precipitation ring.
D) log of the diameter of the precipitation ring.

Question 8

A solution has 4 pentomeric IgM antibodies per microliter.What concentration of antigen molecules is necessary for the solution to be in the zone of equivalence? The antigen has 4 identical epitopes on each molecule.

A) 4 antigen molecules per microliter
B) 5 antigen molecules per microliter
C) 10 antigen molecules per microliter
D) 20 antigen molecules per microliter

Question 9

Rate nephelometry measures the change in what factor over time?

A) Antigen concentration
B) Antibody concentration
C) Antigen breakdown
D) Antigen-antibody complex formation

Question 10

The law of mass action states that:

A) any free reactants will rapidly bind together.
B) the number of antibody binding sites must equal the number of antigen binding sites.
C) free reactants are in equilibrium with bound reactants.
D) the rate of binding equals the rate of dissociation.

Question 11

Which antibody class may require the use of an enhancement technique to visualize the reaction?

A) IgM
B) IgG
C) IgA
D) IgE

Question 12

A serological test that uses red blood cells coated with exogenous antigens such as bacterial polysaccharides as a method to detect patient antibodies against those exogenous antigens is called:

A) latex agglutination.
B) hemagglutination.
C) neutralization.
D) complement fixation.

Question 13

If antibody is uniformly distributed in a gel and antigen is added to a well cut into the gel,the process is called:

A) single diffusion.
B) double diffusion.
C) immunofixation.
D) retrodiffusion.

Question 14

The assembly of particles into visible clumps is called:

A) precipitation.
B) agglutination.
C) equivalence.
D) sensitization.

Question 15

The process by which particulate antigens such as cells aggregate to form larger complexes when specific antibody is present is called:

A) sensitization.
B) precipitation.
C) agglutination.
D) flocculation.

Question 16

Coombs reagent is used for what purpose?

A) To link small antigens on patient red cells
B) To enhance agglutination with IgG-coated red blood cells
C) To enhance agglutination with IgM-coated red blood cells
D) To cause a precipitation reaction with small amounts of antibody

Question 17

Which antibody has the highest avidity for an antigen?

A) IgG containing Fab that each have an affinity of 4 × 10-?/M
B) Secretory IgA containing Fab that each have an affinity of 4 × 10-?/M
C) IgM containing Fab that each have an affinity of 1 × 10-?/M
D) IgE containing Fab that each have an affinity of 1 × 10-?

Question 18

If a serum sample does not cause agglutination when mixed with a particular antigen,then you should:

A) report that the patient does not have antibody against that antigen.
B) test a more diluted sample to overcome possible prozone effects.
C) increase the particle surface charge by altering the pH.
D) decrease the viscosity of the sample.

Question 19

In performing blood typing using the tube method,if the red cell button is not resuspended properly,what are the most likely results?

A) False positive
B) False negative
C) Does not affect the results
D) Makes the reaction weaker

Question 20

A serological reaction is set up in which the antigen is bound to a large carrier,the antibody is soluble,and the antigen and carrier bind and form an insoluble complex that is detected macroscopically.What type of assay is described?

A) Precipitation
B) Agglutination
C) Flocculation
D) Neutralization

Question 21

Which of the following is true of a reverse agglutination test?

A) The antigen is a natural particle.
B) Antigen molecules are artificially bound to particles.
C) Antibody is attached to particles.
D) The antigen-antibody reaction is competitive (no agglutination indicates a positive result).

Question 22

In immunofixation electrophoresis,antibody is:

A) distributed uniformly throughout the gel.
B) applied on the top surface of the gel.
C) added to troughs cut into the gel.
D) driven through the gel by application of electrical current.

Question 23

A patient's serum sample is added to a solution containing particulate antigen,but no agglutination is observed.What should be done next?

A) Perform serial dilutions of the sample.
B) Report out as a negative test.
C) Add more particulate antigen.
D) Read the reaction in dim light.

Question 24

If crossed lines result in an Ouchterlony immunodiffusion reaction with antigens A and B,this indicates that antigens A and B:

A) are identical.
B) are entirely different.
C) share a common epitope, with A being a more complex antigen.
D) share a common epitope, with B being a more complex antigen.

Question 25

Which best describes hemagglutination tests?

A) Patient antibody reacts with hemoglobin.
B) The reaction involves red blood cells.
C) Patient antibody is always involved.
D) Hemoglobin binds to antigen.

Question 26

Which of the following is characteristic of a passive agglutination test?

A) The antigen is naturally found on particles.
B) Antigen molecules are artificially bound to particles.
C) Antibody is attached to particles.
D) The antigen-antibody reaction is competitive (no agglutination indicates a positive result).

Question 27

The particle-counting immunoassay method counts the number of:

A) agglutinated particles.
B) free antibody molecules.
C) free latex particles.
D) antigen-antibody bonds.

Question 28

The visibility of an agglutination reaction involving IgG can be enhanced by adjusting which factor?

A) Changing to a colder temperature
B) Diluting out the particulate antigen
C) Decreasing the light to read the reaction
D) Adding anti-human Fc

Question 29

In an agglutination reaction,the antibody isotype that most effectively overcomes the electrostatic repulsion between particles is:

A) IgA.
B) IgE.
C) IgG.
D) IgM.

Question 30

Which best characterizes agglutination inhibition reactions?

A) The antigen is naturally expressed on particles.
B) Antigen molecules are artificially bound to particles.
C) Antibody is attached to particles.
D) No agglutination indicates a positive result.

Question 31

If an Ouchterlony immunodiffusion pattern shows an arc equidistant between antigens A and B,this indicates that the antigens:

A) are identical.
B) are entirely different.
C) share a common epitope, with A being a more complex antigen.
D) share a common epitope, with B being a more complex antigen.

Question 32

Agglutination reactions run at room temperature are appropriate for antigen-antibody reactions involving:

A) IgA.
B) IgE.
C) IgG.
D) IgM.

Question 33

The AFFINITY of antigen-antibody binding is influenced by which of the following?

A) How well the antigen fits into the binding site on Fab
B) The number of Fab sites on the immunoglobulin
C) The number of antigens in the reaction
D) The charge distribution on Fc

Question 34

If an Ouchterlony immunodiffusion pattern shows an arc between antigens A and B with an extended line pointing to antigen B,this indicates that the antigens:

A) are identical.
B) are entirely different.
C) share a common epitope, with A being a more complex antigen.
D) share a common epitope, with B being a more complex antigen.

Question 35

The end-point radial immunodiffusion assay:

A) is read after antigen-antibody equivalence is reached.
B) is the most rapid immunodiffusion method.
C) requires only a negative control for interpretation.
D) can be converted to a kinetic method by application of electrical current.