Chapter 6 The ABO Blood Group System

Question 1

Forward grouping is defined as:

Answer 1

detecting antigen(s) on an individual’s red cells via reagent antisera

Question 2

What percentage of the white population has type O blood?

Answer 2

45%

Question 3

Why is reverse grouping not performed on cord blood specimens?

Answer 3

Antibodies are generally not present at birth

Question 4

Which of the following is unique to the ABO system when compared with other blood group systems?

Answer 4

Individuals have antibodies to antigens they lack without foreign stimulus

Question 5

How are ABH antigens formed?

Answer 5

production of specific glycosyltransferases add sugars to precursor substances

Question 6

What immunodominant sugar is responsible for H specificity?

Answer 6

L-fucose

Question 7

What does the hh genotype refer to?

Answer 7

Bombay

Question 8

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

Answer 8

glycoprotein

Question 9

What substances are found in a group A secretor?

Answer 9

A, H

Question 10

What is a “lectin”?

Answer 10

seed extracts that agglutinate human cells with moderate specificity

Question 11

What percentage of the blood Type A white population is type A2?

Answer 11

20%

Question 12

What is the source of anti-H lectin?

Answer 12

Ulex europaeus

Question 13

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

Answer 13

differentiating a true B from an acquired-like B

Question 14

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

    a) sample misidentified		
    b) failure to warm reagents
 	c) failure to add reagents
 	d) clerical errors

Answer 14

b) failure to warm reagents

Question 15

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

Answer 15

incubate patient serum and reagent cells for 15 minutes at room temperature

Question 16

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

Answer 16

• anti-B lectin
• acidification of anti-B reagent
• secretor studies

Question 17

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 and recentrifuged in an attempt to resolve the discrepancy?

Answer 17

saline

Question 18

An ABO type on a patient gives the following reactions:
Anti-A Anti-B A1 cells B cells
4+ 4+ Neg Neg

What is the patient’s blood type?

Answer 18

AB

Question 19

The major immunoglobulin class(es) of anti-B in a group A individual is (are):

Answer 19

IgM

Question 20

What are the possible ABO phenotypes of the offspring from the mating of a group A to a group B individual?

Answer 20

AB,A,B,O

Question 21

The immunodominant sugar responsible for blood group A specificity is:

Answer 21

N-acetyl-D-galactosamine

Question 22

What ABH substance(s) would be found in the saliva of a group B secretor?

Answer 22

slight H and B

Question 23

What ABH substance(s) would be found in the saliva of a group O secretor?

Answer 23

heavy H only

Question 24

What ABH substance(s) would be found in the saliva of a group AB secretor?

Answer 24

A, B, and H

Question 25

What ABH substance(s) would be found in the saliva of a group A secretor?

Answer 25

A and slight H

Question 26

The precursor in which A and B antigens are made?

Answer 26

H antigen

Question 27

The precursor substance on erythrocytes is referred to as?

Answer 27

Type 2

Question 28

An ABO type on a patient gives the following reactions:
Anti-A Anti-B Anti-A1 A1 cells B cells
4+ 4+ Neg 2+ Neg

Answer 28

A2B with Anti-A1

Question 29

What is the order of reactivity for H fro greatest to the least amount of H?

Answer 29

O>A2>B>A2B>A1>A1B

Question 30

What reaction would you expect to see in a bombay phenotype?

Answer 30

patient’s cells+Ulex europaeus=no agglutination

Question 31

An example of a technical error that can result in an ABO discrepancy is:

Answer 31

Cell suspension that is too heavy

Question 32

An ABO type on a patient gives the following reactions:
Anti-A Anti-B A1 cells B cells O cells Autocontrol
4+ Neg 2+ 4+ 2+ Neg

Answer 32

Non-ABO alloantibody

Question 33

Paragloboside

2 types of chains

Answer 33

1. type 1

2. type 2

Question 34

Type 1

Answer 34

beta-1,3 linkage
originates in secretions
controlling genes=H,A,B,Se, Le

Question 35

Type 2

Answer 35

beta-1,4 linkage
originates on RBC precursors
controlling genes=HAB

Question 36

ABH antigens on the RBC are constructed on oligosaccharide chains of type 1/2 precursor substance.

Answer 36

type 2

Question 37

type 2 precursor chain (paragloboside)?

Answer 37

RBC-glu-gal-galnac-Beta-1,4 linkage-gal

Question 38

"H" gene
1-enzyme
2-sugar donor
3-sugar added
4-final product

Answer 38

1-a-L-fucosyl-transferase
2-Guanosine-diphosphate L-fucose
3-Fucose (added to type 2 precursor chain)
4-H antigen
RBC-glu-gal-galnac-Beta-1,4 linkage-gal-fuc
*added to the red blood cell precursor

Question 39

"A" gene
1-enzyme
2-sugar donor
3-sugar added
4-final product

Answer 39

1-a-N-acetyl-D-galactosamine transferase
2-Uridine diphosphate-N-acetyl-D-galactose
3-GALNAC
4-A antigen                  
* RBC-glu-gal-galnac-gal-galnac
                                      I
                                     fuc
*must have the H antigen built before you can have A or B
added to the H antigen

Question 40

"B" gene
1-enzyme
2-sugar donor
3-sugar added
4-final product

Answer 40

1-a-D-galactosyl transferase
2-uridine diphosphate galactose
3-galactose
4-B antigen
*RBC-glu-gal-galnac-gal-gal
                                     I
                                    fuc
*added to the H antigen

Question 41

80% of the world’s population is known as?

Answer 41

secretors

*because they have inherited a secretor gene (SeSe or Sese)