Deck 6: Agglutination and Precipitation Reactions: the Unlabeled Immunoassays

Question 1

Equivalence occurs when the

A)antibody-binding sites approximately equal the antigen-binding sites, and the largest complexes form
B)antibody-binding sites approximately equal twice the antigen-binding sites, and the largest complexes form
C)postzone has been passed, more antigen has been added, and the largest complexes form
D)prozone has been passed, more antibody has been added, and the largest complexes form
E)A and C.

Answer 1

antibody-binding sites approximately equal the antigen-binding sites, and the largest complexes form

Question 2

In nephelometry,

A)antibody and antigen form complexes that make the solution cloudy
B)light passes through the solution and is measured directly across from the light source
C)light passes through the solution and is measured at a 10-90º degree angle from the light source
D)A and B
E)A and C

Answer 2

A and C

Question 3

When we ran the serum of a patient who seems to be severely ill with arthritis at the lowest dilution suggested by the latex agglutination kit, the results were negative. What should we do?

A)Report the results to the physician and suggest the patient return in two weeks when his titer might be higher.
B)Report the results to the physician and suggest testing for Lyme disease.
C)Dilute the sample and run it again before the results are reported.
D)Use a different company's kit.

Answer 3

Dilute the sample and run it again before the results are reported.

Question 4

A hapten is best suited for

A)an latex agglutination inhibition assay
B)a postzone equivalence reaction
C)a precipitin reaction
D)a latex agglutination reaction

Question 5

Ka the number of binding sites = the

A)affinity
B)avidity
C)molecular weight
D)turbidimetry number

Question 6

If the antibody's concentration is the same in all the wells at the bottom of the double diffusion gel precipitation reaction in the figure

A)and the antigen is the same in each well, the concentration of the antigen in the wells is higher on the right side of the gel than on the left side
B)and the antigen is the same in each well, the antigen's concentration in the wells is higher on the left side of the gel
C)there is not enough information to choose one answer
D)the reactions on the left side of the gel are in prozone; the reactions on the right side of the gel are in postzone.

Question 7

To measure the amount of rheumatoid factor in a patient's serum, we perform

A)a passive latex agglutination with Fc regions on the particle
B)an inhibition of a passive latex agglutination reaction
C)reverse passive latex agglutination with Fc regions on the beads sticking out
D)reverse passive latex agglutination with Fc regions added in solution

Question 8

The antigen in well A is

A)the same as the antigen in well B
B)not at all like the antigen in well B
C)partially the same as the antigen in well B
D)the same as the antigen in well B but has an extra antigen in the well

Question 9

The antigen in well A is

A)the same as the antigen in well B
B)not at all like the antigen in well B
C)partially the same as the antigen in well B
D)the same as the antigen in well B and has an extra antigen in the well

Question 10

Precipitin reactions are still used clinically for

A)bacterial infections
B)fungal infections
C)cancer
D)viral infections

Question 11

What does the gel in an Ouchterlony contain, and what does the gel in a radial immunodiffusion contains?

A)antigen, antibody
B)agarose only, antibody in agarose
C)antibody, antigen
D)antibody in agarose, agarose only

Question 12

In the Ouchterlony in the figure,

A)A and B have a molecule that shares an epitope, but the molecule from A has an extra epitope
B)A and B have a molecule that shares an epitope, but the molecule from B has an extra epitope
C)A and B do not have a molecule that shares an epitope, and the molecule from A has is a faster diffusion coefficient
D)A and B do not have a molecule that shares an epitope, and the molecule from B has is higher molecular weight

Question 13

In PETINA,

A)the residual nonagglutinating particles are counted
B)the drug in the patient's serum increases turbidity
C)the drug in the patient's serum decreases turbidity
D)the drug in the patients serum decreases the number of residual nonagglutinating particles

Question 14

The zeta potential is

A)the charge on particles that complicates agglutination reaction
B)a charge that can be decreased with low ionic strength saline
C)a charge that is increased with low ionic strength saline
D)A and B
E)A and C

Question 15

A patient has been exposed to an inhaled fungus, and it seems likely that she has a beginning infection. The current approved test for diagnosis is an Ouchterlony test with her antibody sample in a well and several different fungal antigens in wells surrounding it. No precipitin line occurred.

A)The patient does not have this infection.
B)The serum should be repeated at the same concentration.
C)The patient's blood should be drawn again in 2 weeks and retested.
D)None of the above is correct.

Question 16

Nephelometry and turbidimetry differ because

A)although both measure the effect of aggregates on light passing through a solution, turbidimetry measures the light scattered at 10-90°, and nephelometry measures the light that goes directly through the solution
B)although both measure the effect of aggregates on light passing through a solution, turbidimetry measures the light scattered at 10-90°, and nephelometry measures the light that is polarized
C)nephelometry uses instrumentation but turbidimetry does not
D)although both measure the effect of aggregates on light passing through a solution, nephelometry measures the light scattered at 10-90°, and turbidimetry measures the light that goes directly through the solution

Question 17

When a mom and a dad have the same ABO blood group but different RH blood typesand- mom is RH negative and dad RH is positiveto determine if mom has made anti-D-

A)mom can be checked with the indirect agglutination test
B)mom and the baby can be checked with the direct agglutination test
C)mom can be checked with the indirect agglutination test, and baby can be tested with the direct agglutination test
D)mom can be checked with the direct agglutination test, and baby can be checked with the indirect agglutination test

Question 18

Agglutination is

A)less sensitive than precipitation
B)more sensitive than precipitation if the particles are highly charged
C)better with IgM at lower temperatures (4-27°)
D)called passive agglutination when the antigen is naturally part of the particle

Question 19

A plot of D² versus concentration is used

A)after 18 hours by the Fahey method
B)after 18 hours by the Mancini method
C)after 48-72 hours by the Mancini method
D)after 48-72 hours by the Fahey method

Question 20

Nephelometry

A)is less sensitive than turbidimetry and is measured directly across from the beam of light that has gone through the sample
B)is more sensitive than turbidimetry and is measured directly across from the beam of light that has gone through the sample
C)is more sensitive than turbidimetry and is measured at a 10-90° angle from the beam of light that has gone through the sample
D)is less sensitive than turbidimetry and is measured at a 10-90° angle from the beam of light that has gone through the sample

Question 21

The Ouchterlony in the figure shows

A)a line of nonidentity and a line of partial identity
B)two lines of full identity
C)two antigens in Ag X that are not the same as two ags in Ag Y
D)two antigens in Ag Y that are not the same as the one antigen visible in antigen y

Question 22

A)The graph in the figure shows the results of an endpoint incubation of an RID using the Mancini method to plot density squared (d²) versus concentration
B)The graph in the figure shows the results of an endpoint incubation of an RID using the Fahey method to plot d² versus concentration
C)The graph in the figure shows the results of an endpoint incubation of an RID using the Mancini method to plot diameter squared versus concentration.
D)The graph shows none of the above.

Question 23

To increase agglutination, we could

A)decrease viscosity of the media
B)increase the waters of hydration
C)add low ionic strength media
D)bring the temperature up to 56° for optimum antibody binding

Question 24

To measure the amount of a small drug (hapten sized) that is in the patient's serum, can agglutination or precipitation reactions be performed, and if so, how?

A)Yes, agglutination inhibition can be performed as in PETINA.
B)Yes, precipitation inhibition can be performed as in PETINA.
C)No, since this molecule is so small it cannot be cross-linked and thus cannot be measured by precipitation or agglutination
D)Yes, although this molecule is too small for agglutination, it can be used in precipitation

Question 25

The spur in the preceding reaction contains

A)anti-1 and 1
B)anti-2 and 2
C)anti-a and a
D)all of the above

Question 26

The zeta potential is the

A)charge on the particles that will be aggregated
B)effect of the treatment of an antibody molecule with electrophoresis
C)potential that an antibody will aggregate the particles
D)potential that the reaction will occur in the postzone

Question 27

Radial immunodiffusion can be used to measure

A)IgM, IgG, and IgA
B)some complement components
C)IgM, IgG, IgA, and IgE
D)A and B.
E)B and C

Question 28

To determine whether a patient has autoimmune hemolytic anemia, we can add anti-human immunoglobulin to the person's red blood cells, which is

A)a reverse passive test
B)a competitive assay
C)an indirect antiglobulin test
D)a direct antiglobulin test

Question 29

Regarding the affinity of antibody to antigen,

A)Ka = [Ab][Ag]/[AbAg]
B)Ka = [AbAg]/[Ab][Ag]
C)Kd = [Ab][Ag]/[AgAb]
D)none of the above

Question 30

The serum of a patient with pneumonia caused by S. pneumoniae was tested for its ability to aggregate Streptococcus pneumoniae cells, we expect aggregation; however we do not see it because

A)This type of reaction is called a agglutination, and the patient sera did not cause agglutination because of a prozone phenomenon.
B)This type of reaction is called hemagglutination, and the patient sera did not cause agglutination because of a prozone phenomenon.
C)This type of reaction is called LAI, and the patient sera did not cause agglutination because of a prozone phenomenon.
D)This type of reaction is called passive agglutination, and the patient sera did not cause agglutination because of a postzone phenomenon.

Question 31

Agglutination is _____ sensitive than precipitation and _________requires that at least the antigen from either the patient or the kit is in a particulate form.

A)more, usually
B)equally, never
C)more, always
D)less, usually

Question 32

A quantitative procedure

A)Ouchterlony
B)double diffusion gel precipitation reaction
C)single diffusion gel precipitation
D)radial immunodiffusion
E)C and D