Deck 6: The Abo Blood Group System

Question 1

Where will the ABO discrepancy occur in cis-AB individuals?

A) Forward grouping with anti-A
B) Reverse grouping with B cells
C) Forward grouping with anti-AB
D) Reverse grouping with A₁ cells

Answer 1

B

Question 2

Serum from a group B individual contains anti-A. When A₂ cells are added to serum and centrifuged, the cells with attached anti-A are removed from serum. What is the name of this technique?

A) Elution
B) Absorption
C) Glycerolization
D) Deglycerolization

Answer 2

B

Question 3

Secretor studies were performed on a person who expressed weak reactions in forward grouping. Only B and H substance were present in the saliva. What is this person's ABO group?

A) O
B) A
C) B
D) AB

Answer 3

C

Question 4

All of the following may result in weak or missing antigens except:

A) presence of blood-group-specific soluble substances (BGSS).
B) Hodgkin's disease.
C) hypogammaglobulinemia.
D) intestinal infection with Escherichia coli.

Question 5

A group O person with warm autoimmune hemolytic anemia may demonstrate weak reactions in the forward grouping due to:

A) red blood cells being coated with antigen.
B) red blood cells being coated with antibody.
C) exposure of T antigen.
D) acquired B-like syndrome.

Question 6

Why can anti-H sometimes be found in an A₁B individual?

A) L-fucose does not attach to precursor substance.
B) The H gene is not inherited.
C) The specific immunodominant sugar blocks the presence of H antigen.
D) The individual does not secrete H substance in secretions.

Question 7

Approximately how many antigen sites exist on a type-A₁ individual's RBC?

A) 1 million
B) 600,000
C) 1,000
D) 5 million

Question 8

Which of the following is not characteristic of antibodies within the ABO system?

A) Antibodies are of IgM Class.
B) Antibodies are naturally occurring.
C) ABO antibodies do not activate complement.
D) ABO antibodies may cause immediate intravascular hemolysis.

Question 9

Where are ABH substances detected in secretors?

A) Tears
B) Saliva
C) Milk
D) All of the above

Question 10

What testing is available that will differentiate between a true B and an acquired B?

A) Anti-B lectin
B) Acidification of anti-B reagent
C) Secretor studies
D) All of the above

Question 11

What is a lectin?

A) A protein produced from immunized rabbits and cloned for specificity
B) A foreign protein that will elicit an immune response in most individuals
C) Seed extracts that agglutinate human cells with moderate specificity
D) A substance that will agglutinate sensitized cells in the presence of complement

Question 12

What other consideration should be made before beginning a subgroup investigation?

A) Patient demographics
B) ABH alteration caused by malignancy
C) Chromosomal aberration
D) Immunization record of patient

Question 13

What is the source of anti-A₁ lectin?

A) Bandeiraea simplicifolia
B) Dolichos biflorus
C) Ulex europaeus
D) All of the above

Question 14

What is the biochemical structure of secreted A, B, and H substances?

A) Glycolipid
B) Glycoprotein
C) Sphingolipid
D) Ceramide

Question 15

Anti-A from a group B individual is primarily what class of immunoglobulin?

A) IgM
B) IgG
C) IgA
D) All of the above

Question 16

How is polyagglutination resolved?

A) Absorption of Tn antigen with anti-T
B) Patient serum is tested with a lectin panel
C) Patient cells are tested with a lectin panel
D) Elution of Tn antigen with chloroquine

Question 17

Cord blood was sent to the laboratory for blood type determination on twins A and B. Baby A demonstrated mixed-field reactions with anti-A and anti-AB and no reactivity with anti-B. Reverse grouping was not performed. Baby B showed a 1+ reaction with anti-A and anti-AB. What could be the reason for the variable reactions?

A) Chimerism
B) A dimorphic cell population
C) Dispermy
D) All of the above

Question 18

Which of the following criteria is used to classify the B subgroups?

A) Agglutination patterns with anti-B, anti-AB, and anti-H
B) Presence of ABH isoagglutinins in serum
C) Absorption studies with anti-B
D) All of the above

Question 19

What substances are found in a group A secretor?

A) AH
B) H
C) BH
D) ABH

Question 20

What ABO group contains the least amount of H substance?

A) A₁
B) A₂
C) A₁B
D) A₂B

Question 21

A type-A person demonstrates a 3+ reactivity with A₁ cells (reverse grouping). The forward grouping with anti-A is 4+. Therefore, the possibility of a subgroup is excluded. B cells demonstrate a 4+ reaction. The antibody screen is weakly positive at 37°C but shows no reactivity at the AHG phase. An antibody panel is performed and anti-M is identified. The patient phenotypes negative for M antigen. How is the ABO discrepancy resolved?

A) Perform reverse grouping at 4°C.
B) Perform reverse grouping with A₁ cells negative for M antigen.
C) Perform reverse grouping with A₁ cells positive for M antigen.
D) Perform forward grouping at 4°C.

Question 22

If a type-A person contains anti-M in his or her serum, what might the reverse grouping type as?

A) A
B) B
C) AB
D) O

Question 23

All of the following are technical errors that could result in ABO discrepancies except:

A) a misidentified sample.
B) failure to warm reagents.
C) failure to add reagents.
D) clerical errors.

Question 24

Which ABO group's reaction will be the weakest with anti-H lectin?

A) A₁
B) B
C) A₂B
D) AB

Question 25

What is the cause of polyagglutination in most cases?

A) Exposure of anti-T caused by bacterial contamination
B) Exposure of T antigen caused by bacterial contamination
C) Hypergammaglobulinemia
D) Exposure of I antigen caused by bacterial contamination

Question 26

What is the source of anti-B lectin?

A) Bandeiraea simplicifolia
B) Ulex europaeus
C) Dolichos biflorus
D) All of the above

Question 27

Why is reverse grouping not performed on cord blood specimens?

A) Antigens are not present at birth.
B) Antibodies are generally not present at birth.
C) Antibody titer is too high.
D) Antigens are too weak.

Question 28

Two drops of serum are added to one drop of A₁ cells, and two drops are added to one drop of B cells; the two tubes are centrifuged. The tubes show reactivity when read macroscopically. This is an example of:

A) forward grouping.
B) reverse grouping.
C) antibody screen.
D) crossmatch.

Question 29

If a group O mother gives birth to a group A baby, which of the following antibodies is usually responsible for crossing the placenta and causing hemolytic disease of the newborn (HDN)?

A) Anti-AB
B) Anti-B
C) Anti-A
D) Anti-H

Question 30

What percentage of the type A population is A₂?

A) 1%
B) 10%
C) 20%
D) 80%

Question 31

An elderly patient is documented as being type O. The forward grouping is negative with anti-A and anti-B. The reverse grouping shows no reactivity with A₁ cells and B cells. What can be done to correct the discrepancy?

A) Incubate the patient's serum and reagent cells for 15 minutes at room temperature.
B) Incubate the patient's serum and reagent cells for 15 minutes at 37°C.
C) Perform an antibody screen.
D) Incubate the patient's cells and serum for 15 minutes at room temperature.

Question 32

All of the following is true regarding formation of the ABH antigens except:

A) H gene inheritance is independent of ABO gene inheritance.
B) A, B, and H antigens are formed from the same precursor material.
C) A type 1 structure refers to a beta 1-2 linkage.
D) A type 2 structure refers to a beta 1-4 linkage.

Question 33

When performing secretor studies, what is omitted in the control tube but present in the patient tube?

A) Antiserum
B) 5% B cells
C) Saliva
D) 5% O cells

Question 34

What is used to stimulate saliva secretion in secretor studies?

A) Tongue depressor
B) Paraffin wax
C) Chewing gum
D) Water

Question 35

The ABO group antibodies are primarily:

A) alloantibodies.
B) autoantibodies.
C) naturally occurring.
D) drug induced.

Question 36

What percentage of the white population has type-O blood?

A) 45%
B) 10%
C) 4%
D) 32%

Question 37

Reverse grouping showed negative reactions with A₁ and B cells. Forward grouping showed positive reactions with A, B, and AB antisera. What blood type is consistent with these results?

A) A
B) B
C) AB
D) O

Question 38

What immunodominant sugar is responsible for H specificity?

A) D-galactose
B) L-fucose
C) N-acetyl-D-galactosamine
D) D-glucose

Question 39

All of the following statements are true concerning ABH soluble substances except:

A) the first sugar in the precursor substance is N-acetylgalactosamine.
B) the precursor chain is type 2 (beta 1-4 linkage).
C) ABH structures are glycoproteins.
D) L-fucosyltransferase production is regulated by the Se system.

Question 40

Mixed-field agglutination encountered in ABO forward grouping may be caused by:

A) A_3.
B) cold reactive autoagglutinins.
C) abnormal concentrations of serum proteins.
D) para-Bombay.

Question 41

What is the most important use for anti-B lectin?

A) Differentiating B₁ from B₂
B) Differentiating secretors from nonsecretors
C) Differentiating a true B from an acquired-like B
D) All of the above

Question 42

How are ABH antigens formed?

A) Production of specific glycosyltransferases add sugars to precursor substances
B) Recombinant gene technology
C) ABO genes code for production of antigens
D) All of the above

Question 43

Approximately how many antigen sites can be found on A₂ cells?

A) 1 million
B) 10,000
C) 260,000
D) 500,000

Question 44

What is the only possible phenotype of an offspring produced from two group O parents?

A) A
B) B
C) AB
D) O

Question 45

What immunodominant sugar is responsible for B specificity?

A) D-galactose
B) L-fucose
C) N-acetyl-D-galactosamine
D) D-glucose

Question 46

A patient was previously typed as blood group O. Forward grouping was negative with anti-A and anti-B. Reverse grouping showed reactivity with A₁ cells and B cells. The technologist reported this patient's type as A. What technical error occurred?

A) Sample misidentified
B) Failure to add reagents
C) Clerical error
D) Sample mix-up

Question 47

What is the source of anti-H lectin?

A) Bandeiraea simplicifolia
B) Ulex europaeus
C) Dolichos biflorus
D) All of the above

Question 48

Which blood group contains the highest concentration of H antigen?

A) A₂
B) B
C) AB
D) O

Question 49

A patient who was recently diagnosed with an obstructed bowel became septic from Proteus vulgaris. Prior to surgery, a routine type and screen was performed. Though this person typed as an A 2 years ago, his forward type is consistent with an AB individual, albeit weaker in strength with anti-B. What is the reason for this discrepancy?

A) Acquired "B"
B) Technical error
C) Incorrect patient history
D) Contaminated anti-A

Question 50

What does the hh genotype refer to?

A) Lewis
B) Sid
C) Bombay
D) Kell

Question 51

Individuals with group B blood are more common among which populations?

A) Black/Asian
B) Asian/white
C) White/black
D) Hispanic/white

Question 52

Reverse grouping was performed on an AB person. The technologist observed a very weak agglutination macroscopically. The cells appeared as "stacked coins" under a microscope. Which reagent should be added to the tube before recentrifugation in an attempt to resolve the discrepancy?

A) Serum
B) Saline
C) Water
D) LISS

Question 53

All of the following is consistent with A3 individuals except:

A) "A" substance in saliva.
B) mixed field agglutination with anti-A.
C) 4,000 antigenic sites on red blood cells.
D) a variable amount of "A" transferase in serum.

Question 54

What percentage of A₂ individuals produce anti-A₁?

A) 5%
B) 20%
C) 50%
D) 80%

Question 55

Which of the following indicates secretor gene control overproduction of H substance?

A) L-fucosyltransferase is found in the saliva of secretors.
B) D-galactosyltransferase is found in saliva of secretors.
C) N-acetylgalactosaminyltransferase is found in saliva of secretors.
D) D-glycosyltransferase is found in saliva of secretors.

Question 56

What percentage of individuals inherit the secretor gene?

A) 15%
B) 50%
C) 80%
D) 98%

Question 57

Which substance must be formed first before A or B specificity is determined?

A) I
B) O
C) Bombay
D) H

Question 58

Forward grouping is defined as:

A) detecting antibody on an individual's red blood cells via reagent antisera.
B) detecting antigen(s) on an individual's red blood cells via reagent antisera.
C) detecting ABO group antibody via reagent red blood cells.
D) detecting ABO group antigen via reagent red blood cells.

Question 59

The forward grouping of a patient showed no agglutination of patient cells with anti-A, anti-B, or anti-AB reagent antisera. The reverse grouping showed agglutination with A₁ and B cells. What is this person's ABO group?

A) A
B) B
C) AB
D) O

Question 60

What would be a possible genotype of an A₂B individual?

A) A₁B
B) A₂B
C) A₂O
D) A₂A₂

Question 61

All of the following may depress antigen expression except:

A) leukemia.
B) lymphoma.
C) coronary heart disease.
D) Hodgkin's disease.

Question 62

Weak agglutination with anti-A typing sera is to be expected with which of the following blood groups?

A) A₁
B) A₂
C) A₃
D A_2B

Question 63

Persons who inherit the h allele do not produce transferase necessary for formation of the H structure.

A) L-fucosyl
B) N-acetylgalactosaminyl
C) D-galactosyl
D) D-glucosyl

Question 64

Antibody titers specific to antigens from the ABO system are typically highest:

A) when the patient is a newborn.
B) when the patient is around 10 years old.
C) when the patient is around 30 years old.
D) when the patient is around 60 years old.

Question 65

An AB male mates with an AB female. What could be the genotype of the offspring?

A) AB
B) AA
C) BB
D) All of the above

Question 66

The state in which an individual's red blood cells are agglutinated by all sera regardless of blood type is called:

A) panagglutination.
B) polyagglutination.
C) sensitization.
D) leukoagglutination.

Question 67

All of the following may result in rouleaux formation except:

A) Waldenstrom's macroglobulinemia.
B) Wharton's jelly in cord blood.
C) leukemia.
D) dextran.

Question 68

All of the following are tests performed in the blood bank to classify subgroups of A except:

A) anti-H lectin reactivity.
B) absorption.
C) LISS enhancement.
D) elution.

Question 69

What percentage of the type-A population are A₁?

A) 80%
B) 50%
C) 20%
D) 10%