Deck 7: Labeled Immunoassays

Question 1

In a competitive immunoassay, the

A)amount of signal is directly proportional to the amount of patient's antibody and can be determined from a standard curve
B)amount of signal is inversely proportional to the amount of patient's antibody and can be determined from a standard curve
C)amount of signal is proportional to the square of the patient's antibody concentration
D)amount of signal is inversely proportional to the square of the antibody concentration

Answer 1

amount of signal is inversely proportional to the amount of patient's antibody and can be determined from a standard curve

Question 2

Which of the following requires a trigger to measure the signal?

A)a fluorescent immunoassay
B)an enzyme immunoassay
C)a chemiluminescent assay
D)a colloid immunoassay

Answer 2

a chemiluminescent assay

Question 3

In a sandwich assay,

A)the antibody is sandwiched between a capture antigen and a labeled antigen
B)the antigen is sandwiched between a capture antibody and a labeled antibody
C)either A or B
D)none of the above

Answer 3

either A or B

Question 4

A western blot differs from a recombinant immunoblot because

A)the antigens on the nitrocellulose strip in the western blot have been blotted directly onto the blot but the antigens on the recombinant immunoblot are electrophoresed onto the blot
B)because the antigens on the nitrocellulose strip in the western blot have been electrophoresed and then blotted onto the blot and the recombinant immunoblot the antigens are just pipetted onto the blot
C)because in a western a direct EIA is performed and in a recombinant immunoblot an indirect EIA is performed
D)because in a western an indirect EIA is performed and in a recombinant immunoblot an indirect EIA is performed

Question 5

The presence of human heterophilic antibody is

A)difficult to predict
B)the result of the patient's interactions with animals of the species used to make the antibody in the assay
C)can cause false positive reactions in capture assays
D)all of the above

Question 6

To remove the effect of a patient's rheumatoid factor, the

A)patient's sample could be diluted in a buffer containing IgG that does not react with the test antigen
B)assay should be run at 37 Cº instead of at room temperature
C)patient's sample could be diluted in nonfat dried milk
D)patient's serum could be diluted in a buffer containing mouse immunoglobulin

Question 7

For a small antigen with one epitope that is in the fluid phase, the best assay would be

A)a capture assay
B)a competitive assay
C)a direct immunofluorescent assay
D)nephelometry

Question 8

Which two labeled immunoassays do not require instrumentation?

A)colloid immunoassay and chemiluminescent assay
B)fluorescent immunoassay and optical immunoassay
C)colloid immunoassay and optical immunoassay
D)fluorescent immunoassay and a colorimetric enzyme immunoassay

Question 9

An additional advantage of an indirect assay is that

A)the indirect step amplifies the reaction and makes the assay more sensitive
B)the indirect step allows for the determination of the class (isotype) of the antibody that is bound
C)A and B
D)none of the above

Question 10

A indirect radioimmunoassay uses a different second antibody binding step because of the radiolabel but the same first antibody binding step as

A)an indirect enzyme immunoassay
B)an indirect fluorescent immunoassay
C)capture assay
D)A and B

Question 11

In analysis of a multiplex bead,

A)one-color fluorescence is measured from the indirect immunoassay
B)one-color fluorescence is measured from the indirect immunoassay signal and one blended color is measured from the bead
C)two-color fluorescence is measured from the indirect immunoassay signal, and 100 different colors are measured from each bead
D)two-color fluorescence is measured from the direct immunoassay signal, and 100 different colors are measured from each bead

Question 12

HAMA

A)is human anti-mouse antibody
B)can cause false positives in capture immunoassaysC can cause false negative reactions in capture immunoassays
C)A and B
D)A and C

Question 13

The kit for the homogeneous assay for methamphetamine comes with methamphetamine linked to glucose-6-phosphate dehydrogenase, and antibody to the drug blocks the action of the enzyme when the patient's serum contains

A)the drug and there is more enzyme reactivity
B)the drug and there is less enzyme reactivity
C)low levels of the drug and there is less enzyme reactivity than without the patient's serum
D)high levels of the drug and there is less enzyme reactivity than without the patient's serum

Question 14

To measure the amount of a 200,000-molecular-weight-tumor antigen in a patient's blood, the best assay is

A)a direct enzyme immunoassay
B)an indirect immunoassay
C)a sandwich immunoassay
D)none of the above

Question 15

Advantage(s) of an indirect assay is(are) that

A)the indirect step amplifies the reaction and makes the assay more sensitive
B)the indirect step allows for the determination of the class (isotype) of the antibody that is bound
C)A and B
D)none of the above

Question 16

A indirect radioimmunoassay uses a different second antibody-binding step because of the radiolabel, but the same first antibody binding step is

A)an indirect enzyme immunoassay
B)an indirect fluorescent immunoassay
C)a capture assay
D)all of the above

Question 17

In analysis of a multiplex bead

A)two-color fluorescence is measured from the indirect immunoassay signal, and 100 different colors are measured from each bead
B)two-color fluorescence is measured from the direct immunoassay signal, and 100 different colors are measured from each bead
C)one-color fluorescence is measured from the indirect immunoassay
D)one-color fluorescence is measured from the indirect immunoassay signal and one blended color is measured from the bead

Question 18

In the homogeneous assay for methamphetamine, the kit comes with methamphetamine linked to glucose-6-phosphate dehydrogenase, and antibody to the drug blocks the action of the enzyme when the patient's serum contains

A)low levels of the drug and there is less enzyme reactivity than without the patients serum
B)high levels of the drug and there is less enzyme reactivity than without the patient's serum
C)the drug and there is more enzyme reactivity
D)the drug and there is less enzyme reactivity

Question 19

Which of the following is a homogeneous assay?

A)a sandwich assay
B)an immunocolloid assay
C)a fluorescence polarization immunoassay
D)a multiplex assay

Question 20

You have a patient who has rheumatoid factor. If you are performing an assay for various infectious diseases in which you capture the patient's IgM, add the antigen, and then add a labeled antibody to the antigen, the

A)reactions with all antigens tested would be positive
B)reactions with all antigens tested would be negative
C)controls would be negatively affected
D)assay would not be affected

Question 21

Two assays which are often used for point of care tests are

A)optical immunoassays and radioimmunoassay
B)optical immunoassays and colloid immunoassays
C)enzyme immunoassays and fluorescent immunoassays
D)multiplex assays and colloid immunoassays

Question 22

Which of the following assays requires a trigger

A)a colloid immunoassay
B)a chemiluminescent assay
C)a radioimmunoassay
D)a fluorescent immunoassay

Question 23

In a sandwich assay

A)the antibody is sandwiched between a capture antigen and a labeled antigen
B)the antigen is sandwiched between a capture antibody and a labeled antibody
C)either A or B
D)none of the above

Question 24

In a capture assay for IgM that reacts with rubella, an antibody to human IgM binds the patient IgM, rubella antigen from the kit is added, and then an enzyme labeled antibody to rubella is added. What would happen to this assay if the patient had rheumatoid factor but no IgM antibodies to rubella?

A)The patient would appear positive for IgM rubella antibodies unless bovine serum albumin was added as a nonspecific blocker.
B)The patient would appear positive for IgM rubella antibodies unless nonfat dried milk was added as a nonspecific blocker.
C)The patient would appear positive for IgM rubella antibodies unless human IgG that did not react with rubella was added as a specific blocker.
D)The patient would appear negative for IgM rubella antibodies unless human IgG that did not react with rubella was added as a specific blocker.

Question 25

In the following two reactions, the test tube is washed and centrifuged and only the reaction on the beads stays in the tube. The reaction on the right

A)includes the addition of the patient antigen and results in increased color
B)includes the patient antigen and results in decreased color
C)is a heterogeneous assay
D)makes this a capture assay

Question 26

Which of the following assays uses a trigger before the signal can be read?

A)a homogeneous assay
B)a radioimmunoassay
C)a fluorescent immunoassay
D)a chemiluminescent assay

Question 27

The reaction shown in the figure is

A)a sandwich immunoassay
B)a capture immunoassay
C)an indirect immunoassay
D)a direct immunoassay
E)A and B

Question 28

The best name for the assay in the figure below would be

A)a capture enzyme immunoassay
B)a double capture enzyme immunoassay
C)a direct enzyme immunoassay
D)an indirect enzyme immunoassay

Question 29

A fluorescent polarization assay is

A)an inhibitory labeled immunoassay
B)a multiplex assay
C)a heterogeneous labeled immunoassay
D)a homogeneous labeled immunoassay

Question 30

The presence of human heterophilic antibody

A)is difficult to predict
B)results from the patient's interactions with animals of the species used to make the antibody in the assay
C)can cause false positive reactions in capture assays
D)all of the above

Question 31

Optical immunoassays are based on

A)a change in the color of light reflected from the surface when ag and ab are bound
B)a change in color seen in a fluorescent immunoassay
C)the use of immunochromatography
D)chemiluminescence

Question 32

HAMA

A)is human anti-mouse antibody
B)can cause false positives in capture immunoassays in which monoclonal antibodies are used
C)can cause false negative reactions in capture immunoassays in which mouse monoclonal antibodies are used
D)A and B
E)A and C

Question 33

In the assay in the preceding figure, if the patient had rheumatoid factor

A)the test would be a false negative
B)and high titers of the antibody to the antigen, the test would be a false negative
C)the test results would be unaffected
D)the test would be a false positive

Question 34

The first labeled assays developed were

A)radioimmunoassay
B)chemiluminescent immunoassays
C)enzyme immunoassays
D)fluorescent immunoassays

Question 35

Which is most sensitive?

A)an Ouchterlony reaction
B)an agglutination reaction
C)a homogeneous labeled immunoassay
D)a heterogeneous labeled immunoassay