Deck 8: Immunochemical Techniques

Question 1

Which of the following statements is correct regarding the relationship between immunological quantification by laboratory analysis and biological functionality of the analyte?

A)Immunological quantification and biological functionality are always very closely aligned because of the specificity of the antigen-antibody reaction.
B)Immunological quantification is a more important consideration than biological functionality, because immunological quantification more correctly predicts the activity of the analyte in the body.
C)Immunological quantification may overestimate biological functionality, because the antibody may react with an inactive analyte (such as a metabolite) that contains the antigenic determinant.
D)Immunological quantification will only relate to biological functionality of an analyte if the laboratory analysis is performed on a fresh biological sample within 30 minutes of the time it is received in the laboratory.

Answer 1

Immunological quantification may overestimate biological functionality, because the antibody may react with an inactive analyte (such as a metabolite) that contains the antigenic determinant.

Question 2

Which of the following best describes the visualization step in the Western blot technique?

A)use of a stain specific for the antigen separated
B)reaction with a labeled antihuman immunoglobulin antibody
C)the presence of a fluorescent pigment in the transfer medium
D)the UV/Vis light-absorption properties of the separated antigen

Answer 2

reaction with a labeled antihuman immunoglobulin antibody

Question 3

Suppose your laboratory uses a competitive binding assay with a labeled antigen that incorporates spectrophotometry for the measurement of a particular antigen.As the amount of measured antigen ________ in the patient sample, the absorbance of the test solution will ________.

A)increases, increase
B)increases, decrease
C)decreases, decrease
D)both a and c are correct

Answer 3

increases, decrease

Question 4

In competitive indicator-labeled immunoassays, the label is typically placed on the ________ in the reagent and is used to measure ________ in the patient sample.

A)antigen, antigen
B)antigen, antibody
C)antibody, antigen
D)antibody, antibody

Question 5

The direct Coombs' test measures the presence of antibody _______, and the indirect Coombs' test measures _______.

A)in the serum, antigens on cells
B)on cells, antigens on cells
C)in the serum, free antibodies in the serum
D)on cells, free antibodies in the serum

Question 6

Monoclonal antibodies are antibodies that are:

A)derived from a single line of cells that are directed toward multiple epitopes on an antigen
B)derived from a single line of cells that are directed toward a specific single epitope on an antigen
C)derived from multiple cell lines that are directed toward multiple epitopes on an antigen
D)derived from multiple cell lines that are directed toward a specific single epitope on an antigen

Question 7

Which one of the following sample conditions would be acceptable in complement fixation testing?

A)a hemolyzed sample
B)a lipemic sample
C)plasma collected in EDTA
D)plasma collected in heparin

Question 8

Polyclonal antibodies are antibodies that are:

A)derived from a single line of cells that are directed toward multiple epitopes on an antigen
B)derived from a single line of cells that are directed toward a specific single epitope on an antigen
C)derived from multiple cell lines that are directed toward multiple epitopes on an antigen
D)derived from multiple cell lines that are directed toward a specific single epitope on an antigen

Question 9

Which of the following situations would produce a false increase in light scatter, causing falsely elevated results by immunonephelometry?

A)experimental conditions where the antibody is not in excess
B)hyperlipidemia using end-point immunonephelometry
C)hyperlipidemia using rate immunonephelometry
D)use of a hemolyzed sample with rate immunonephelometry

Question 10

What is the sensitivity range typically seen with indicator-labeled immunoassays?

A)g/L
B)mg/L
C)mg/dL
D)ng/mL

Question 11

____________ is the most sensitive technique using precipitation as an endpoint.

A)Immunofixation
B)Immunonephelometry
C)Radioimmunoassay
D)Fluorometric immunoassay

Question 12

Considering the principles of agglutination reactions, which of the following statements is incorrect?

A)Antigens with single antigenic determinant sites will not result in agglutination.
B)IgG is more efficient at agglutination than IgM.
C)Agglutination reactions are generally used to detect antibody.
D)Reverse agglutination reactions are generally used to detect soluble antigens.

Question 13

In the Western blot technique, antigens separated by the electrophoretic step are blotted onto a strip of:

A)nitrocellulose paper
B)polyacrylamide gel
C)agarose gel
D)neutral agar

Question 14

Which of the following provides the correct explanation for a decrease in light scatter as concentration of hapten (such as a drug) increases in nephelometric inhibition immunoassay (NINIA)?

A)As the concentration of hapten (drug) increases, the excess of antibody decreases, resulting in less light scatter.
B)As the concentration of hapten (drug) increases, more soluble hapten (drug)-antibody complexes form, reducing the amount of light scatter.
C)As the concentration of hapten (drug) increases, more hapten (drug)-antibody complexes form, which fix complement and destroy the complex, reducing the amount of light scatter.
D)As the concentration of hapten (drug) increases, more insoluble hapten (drug)-antibody complexes form, resulting in less light scatter.

Question 15

In antiglobulin testing, the purpose of adding Coombs' reagent is to:

A)provide a bridge between non-agglutinated particles to establish cross-linking to achieve agglutination
B)solubilize particles in order for agglutination to disappear, allowing any following reactions to be more evident
C)inactivate complement
D)activate complement

Question 16

Suppose your laboratory uses a sandwich immunoassay to measure a specific hormone.Following release of a patient's results, the physician questioned the results because they did not match with the patient's symptoms; the results appear falsely elevated.What steps should be taken to evaluate the physician's concerns?

A)Rerun the assay on the original patient sample specimen with fresh reagent.
B)Pre-incubate the patient sample with non-immune globulins before running the sandwich immunoassay.
C)Rerun the assay with fresh controls.
D)Decrease the temperature of the reaction to decrease the results to a more suitable level.

Question 17

Often when performing immunoassays, it is important to know the titer of the antibody.The titer defines:

A)the amount of specific antibody present
B)the affinity of the antibody for the antigen being measured
C)the avidity of the antibody for the antigen being measured
D)the specificity of the antibody for the antigen being measured

Question 18

One of the factors that influences agglutination reactions is the presence of a zeta potential, a negative surface charge, which must be overcome to permit cross-linking and agglutination.Which of the following steps can assist in overcoming the zeta potential?

A)Increase the ionic strength of the medium.
B)Adjust the pH of the medium to physiological pH.
C)Increase the viscosity of the medium.
D)All of the above will assist in overcoming charge repulsion.

Question 19

Suppose your laboratory uses a noncompetitive labeled-antibody immunometric technique that incorporates spectrophotometry for the measurement of a particular antigen.As the amount of measured antigen present in the patient sample ________, the absorbance of the test solution will ________.

A)increases, increase
B)increases, decrease
C)decreases, decrease
D)both a and c are correct

Question 20

Complement fixation assays are measured by:

A)nephelometry
B)densitometry
C)spectrophotometry
D)direct visual observation of agglutination