1S [LEC]: ABO Blood Group System (subgroups + discrepancies) Flashcards by 3sha Ann

Q

A subgroups were described by ___ in ___

A

Von Dungern
1911

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Q

T/F: A subgroups are more common than B subgroups

A

True

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Q

The source of Anti-A1 lectin reagent

A

Dolichos biflorus

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Q

A1 subgroup will react ___ with anti-A1 lectin reagent

A

Positive

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Q

A2 subgroup will react ___ with anti-A1 lectin reagent

A

Negative

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Q

Antigen/s present in A2 subgroup

A

A antigen only

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Q

Antigen/s present in A1 subgroup

A

A & A1

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Q

__% of all group A individuals are A1

A

80%

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Q

__% of all group A individuals are A2 or weaker subgroups

A

20%

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Q

__% of A2 individuals produce anti-A1 in their serum

A

1-8%

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Q

__% of A2B individuals produce anti-A1

A

22-35%

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Q

A1 antibody is a naturally-occurring ___ cold-reacting antibody

A

IgM

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Q

T/F: A1 antibody is likely to cause transfusion reaction

A

False (it usually reacts only at temperatures <37C hence will not react during transfusion)

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Q

A1 antibody is clinically significant if reactive at what temperature?

A

37C

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Q

Found in greatest concentration on the RBCs of group O individuals

A

H antigen

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Q

Which A subgroup has detectable H antigen?

A

A2 (in the presence of an A2 gene, only some of the H antigen is converted to A antigens; the remaining H antigen is detectable on the cell)

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Q

Most efficient subgroup to convert the H antigen

A

A1B

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Q

Enumerate the ABO blood groups (and subgroups) from greatest amount of H antigen to least amount of H antigen

A

O > A2 > B > A2B > A1 > A1B

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Q

Seed extracts that agglutinate human cells with some degree of specificity

A

Lectins

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Q

Give the source of the lectin:

Anti-H

A

Ulex europaeus

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Q

Give the source of the lectin:

Anti-A

A

Helix pomatia

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Q

Give the source of the lectin:

Anti-A1

A

Dolichos biflorus

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Q

Give the source of the lectin:

Anti-B

A

Griffonia simplicifolia

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Q

Give the source of the lectin:

Anti-M

A

Iberis amara

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Give the source of the lectin: Anti-N

Molucella laevis Bauhinia purpura

Give the source of the lectin: Anti-T

Arachis hypogaea

Give the source of the lectin: Anti-Tn

Salvia sclaera

The Bombay phenotype was first reported by ___ in ___ (year) in ___ (place)

Bhende 1952 Bombay, India

Phenotype that results from inheritance of a double dose of h gene

Bombay Phenotype

Inheritance pattern of Bombay Phenotype

Autosomal recessive

Phenotype where the RBCs either completely lack H antigens or have small amounts of H antigen present

Para-Bombay Phenotype

In Bombay Phenotype, there is a mutation in the ___ (H gene) and ___ (Se gene) producing a silenced gene

FUT1 FUT2

Occur when unexpected reactions are obtained n the forward and/or reverse grouping

ABO discrepancies

One of the resolutions in ABO discrepancies is the use of what solution?

Saline suspension

One of the resolutions in ABO discrepancies is the use of which blood type?

O, Rh-compatible RBCs (typically O-)

Type of ABO discrepancy: Weakly reacting or missing antibodies; unexpected reactions in the reverse grouping

Group I Discrepancy

Type of ABO discrepancy: More common

Group I Discrepancy

In group I discrepancy, if the patient is an elderly individual or has hypogammaglobulinemia, the serum must be incubated with ___ and ___ at RT for 15-30 mins

Reagent A1 B cells

In group I discrepancy, ___ and ___ must always be tested with reverse typing

Auto control O cell control

Small to large agglutinates with unagglutinated cell

Mixed-field agglutination

Mixed-field agglutination may appear as ___ or ___

halo puff of smoke

This type of reaction may be due to patient receiving non-ABO-type specific RBCs, ABO subgroups, bone marrow or HSC transplant

Mixed-field agglutination

Type of ABO discrepancy: Probably the least frequently encountered

Group II Discrepancy

Type of ABO discrepancy: Caused by weakly reacting or missing antigens

Group II Discrepancy

Type of ABO discrepancy: Acquired B phenomenon

Group II Discrepancy

Type of ABO discrepancy: Leukemia

Group II Discrepancy

Resolution of group II discrepancy that could promote antigen-antibody reaction

Incubation at RT for 30 mins

One of the resolutions of group II discrepancy is testing the patient's serum or plasma against ___

autologous RBCs

Type of ABO discrepancy: Discrepancies between forward and reverse groupings

Group III Discrepancy

Type of ABO discrepancy: Caused by protein or plasma abnormalities

Group III Discrepancy

Stacking of RBCs in a coin-like fashion

Rouleaux

Type of ABO discrepancy: Result in rouleaux formation or pseudoagglutination

Group III Discrepancy

Type of ABO discrepancy: Caused by elevated levels of globulin from certain disease states

Group III Discrepancy

Type of ABO discrepancy: Wharton's jelly in cord blood samples

Group III Discrepancy

Type of ABO discrepancy: The case of Chimera twins

Group I Discrepancy

One of the resolutions for group III discrepancy is the ___ to visualize true agglutination

Saline replacement technique

A reaction where RBC clumping remains after addition of saline

True agglutination

In the saline replacement technique, the ___ is removed and replaced by an equal volume of saline

Serum

In group III discrepancy, the cord blood sample is ___ to resolve the discrepancy

thoroughly washed (6-8x) with saline

Type of ABO discrepancy: Discrepancies between forward and reverse groupings due to miscellaneous problems

Group IV Discrepancy

Type of ABO discrepancy: Caused by cold reactive autoantibodies

Group IV Discrepancy

Type of ABO discrepancy: Caused by circulating RBCs of more than one ABO group due to RBC transfusion or marrow/SC transplant

Group IV Discrepancy

Type of ABO discrepancy: Caused by ABO isoagglutinins

Group IV Discrepancy

Type of ABO discrepancy: Caused by unexpected non-ABO alloantibodies

Group IV Discrepancy

In group IV discrepancy, the incubation of RBCs is done at 37C and washed with saline thrice. If this is unresolved, the RBCs are treated with ___

0.01 M Dithiothreitol (DTT)

In group IV discrepancy, ___ and ___ could be performed

Cold autoabsorption Antibody identification panel

Give the possible blood type: [Forward] Anti-A: 4+ Anti-B: 2+ [Reverse] A1 Cells: 0 B Cells: 4+

A

Give the possible blood type: [Forward] Anti-A: 4+ Anti-B: 4+ [Reverse] A1 Cells: 2+ B Cells: 2+

AB

Give the possible blood type: [Forward] Anti-A: 2+ Anti-B: 4+ [Reverse] A1 Cells: 4+ B Cells: 2+

B

Give the possible blood type: [Forward] Anti-A: 4+ Anti-B: 4+ [Reverse] A1 Cells: 1+ B Cells: 0

A2B

T/F: A2 antigen usually reacts with Anti-H

True

Antigens missing in Bombay Phenotype

A, B, H

Antibodies present in Bombay Phenotype

Anti-A, Anti-B, Anti-H

Type of ABO discrepancy: Newborn/ old age

Group I Discrepancy

A test for autoantibody and alloantibody

Autocontrol

Type of ABO discrepancy: Caused by subgroups

Group II Discrepancy

Control for forward typing

Bovine serum albumin

Give the possible blood type: [Forward] Anti-A: 0 Anti-B: 0 [Reverse] A1 Cells: 0 B Cells: 0

O (probably an infant or an elderly)

Give the possible blood type: [Forward] Anti-A: 0 Anti-B: 1+ [Reverse] A1 Cells: 4+ B Cells: 4+

O