Deck 10: Agglutination Methods

Question 1

With agglutination inhibition in pregnancy testing,a negative result is evidenced by:

A) agglutination.
B) no agglutination.

Answer 1

agglutination.

Question 2

The first phase of agglutination represents:

A) physical attachment of antibody molecules to antigens on the erythrocytic membrane.
B) physical attachment of antigens to antibody molecules on the erythrocytic membrane.
C) a reversible chemical reaction.
D) both a and c

Answer 2

both a and c

Question 3

The most efficient type of antibodies in agglutination reactions are:

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

Answer 3

IgM.

Question 4

MATCHING
Match the following terms with the correct definition.

Hemagglutination

A)Uses antibodies bound to a particle to enhance the visibility of the reaction
B)Based on the interaction of soluble antigen with antibody
C)Detects antibodies with erythrocyte antigens

Question 5

Match the term with the appropriate description.

Postzone phenomenon

A)The zone in which optimum precipitation occurs
B)An excessive antibody concentration that produces a FALSE -negative reaction
C)An excessive antigen concentration that results in no lattice formation
D)An equal amount of antigen and antibody concentrations

Question 6

An artificial carrier could be:

A) latex particles.
B) colloidal charcoal.
C) erythrocytes coated with antigen.
D) both a and b

Question 7

MATCHING
Match the following terms with the correct definition.

Flocculation

A)Uses antibodies bound to a particle to enhance the visibility of the reaction
B)Based on the interaction of soluble antigen with antibody
C)Detects antibodies with erythrocyte antigens

Question 8

The definition of the term agglutination is the:

A) visible expression of the aggregation of antigens and antibodies.
B) formation of a framework in which antigen particles or molecules alternate with antibody molecules.
C) term used to describe the aggregation of particulate test antigens.
D) all of the above.

Question 9

The quality of agglutination or precipitation test results depends on:

A) length of incubation with the serum containing antibody.
B) amount of antigen conjugated to the carrier.
C) pH.
D) all of the above.

Question 10

MATCHING
Match the following terms with the correct definition.

Coagglutination

A)Uses antibodies bound to a particle to enhance the visibility of the reaction
B)Based on the interaction of soluble antigen with antibody
C)Detects antibodies with erythrocyte antigens

Question 11

The lattice hypothesis states that an optimal reaction occurs between antigen and antibody when:

A) an excess of antigen is present.
B) an excess of antibody is present.
C) antigen and antibody are present in approximately equal proportions.
D) reaction takes place at room temperature.

Question 12

If a slide agglutination test is rotated for less than 1 minute,as the directions specify,what source of error can occur?

A) Possible false-positive
B) Possible false-negative
C) Depends on the amount of antibody present in the sample
D) No effect on the results

Question 13

All the following procedures are typically performed by latex agglutination or latex agglutination inhibition assays except:

A) C-reactive protein (CRP).
B) rheumatoid factors (IgG).
C) pregnancy testing.
D) RPR for syphilis.

Question 14

The strength of an agglutination reaction can be enhanced by:

A) centrifugation.
B) use of albumin.
C) use of low ionic strength saline.
D) all of the above.

Question 15

Anti-human globulin (AHG)is used to:

A) substitute for a low titer of antibody.
B) alter the configuration of an antigen.
C) form cross-links between antibodies bound to the surface of erythrocytes.
D) form cross-links between antigens bound to the surface of erythrocytes.

Question 16

Match the term with the appropriate description.

Prozone phenomenon

A)The zone in which optimum precipitation occurs
B)An excessive antibody concentration that produces a FALSE -negative reaction
C)An excessive antigen concentration that results in no lattice formation
D)An equal amount of antigen and antibody concentrations

Question 17

Precipitation is the term applied to:

A) the aggregation of soluble test antigens.
B) the aggregation of soluble test antibodies.
C) either a or b
D) the aggregation of particulate test antigens.

Question 18

Match the type of immunoglobulin with the optimal thermal range.

IgM

A)4° to 22° C
B)18° to 22° C
C)37° C
D)56° C

Question 19

In a group A patient's reverse serum testing,the cells and serum agglutinate because:

A) group A antigen is present on the patient's erythrocytes.
B) group A antigen is present in the patient's serum.
C) anti-group A is present in the patient's serum.
D) both a and c

Question 20

A false-positive latex agglutination assay for pregnancy can be produced by all the following except:

A) cross-reactivity with luteinizing hormone (LH).
B) cross-reactivity with follicle-stimulating hormone (FSH).
C) antisperm antibodies.
D) monoclonal antibody directed against the beta subunit of hCG.

Question 21

Match the grade of the agglutination reaction with the appropriate description.

Weak (±)

A)Tiny aggregates
B)No aggregates
C)Medium-sized aggregates,some free red blood cells (RBCs)
D)Clear supernatant

Question 22

Match the grade of the agglutination reaction with the appropriate description.

4+

A)Tiny aggregates
B)No aggregates
C)Medium-sized aggregates,some free red blood cells (RBCs)
D)Clear supernatant

Question 23

Match the cause of a false-negative agglutination reaction with the appropriate corrective measure.

Anti-human globulin (AHG)malfunction

A)Dilute patient's serum and retest.
B)Wash cells according to directions;use positive and negative quality control (QC)steps.
C)Repeat blood specimen should be collected a week or more later.
D)Calibrate centrifuge to proper speed and time.

Question 24

Match the cause of a false-negative agglutination reaction with the appropriate corrective measure.

Prozone phenomenon

A)Dilute patient's serum and retest.
B)Wash cells according to directions;use positive and negative quality control (QC)steps.
C)Repeat blood specimen should be collected a week or more later.
D)Calibrate centrifuge to proper speed and time.

Question 25

Match the type of immunoglobulin with the optimal thermal range.

IgG

A)4° to 22° C
B)18° to 22° C
C)37° C
D)56° C

Question 26

Match the cause of a false-negative agglutination reaction with the appropriate corrective measure.

Postzone phenomenon

A)Dilute patient's serum and retest.
B)Wash cells according to directions;use positive and negative quality control (QC)steps.
C)Repeat blood specimen should be collected a week or more later.
D)Calibrate centrifuge to proper speed and time.

Question 27

Match the grade of the agglutination reaction with the appropriate description.

2+

A)Tiny aggregates
B)No aggregates
C)Medium-sized aggregates,some free red blood cells (RBCs)
D)Clear supernatant

Question 28

Match the cause of a false-positive agglutination reaction with the appropriate corrective measure.

Overcentrifugation of cells and serum

A)Use a control with saline and no antibody.
B)Read reactions exactly as specified.
C)Calibrate centrifuge to proper speed and time.
D)Use positive and negative QC cells.

Question 29

Match the grade of the agglutination reaction with the appropriate description.

Negative

A)Tiny aggregates
B)No aggregates
C)Medium-sized aggregates,some free red blood cells (RBCs)
D)Clear supernatant

Question 30

Match the cause of a false-positive agglutination reaction with the appropriate corrective measure.

Autoagglutination

A)Use a control with saline and no antibody.
B)Read reactions exactly as specified.
C)Calibrate centrifuge to proper speed and time.
D)Use positive and negative QC cells.