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Liz's Blood Bank Module 1 > ABO Discrepancies > Flashcards

ABO Discrepancies Flashcards

1
Q

Describe the appearance of rouleaux

A
  • Appears as weak (loose) agglutination

- Stacked coins under the scope

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2
Q

Explain why cord blood cells must washed 4-6x before testing

A

Wharton’s Jelly causes spontaneous “agglutination”

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3
Q

Explain the effect of a strong cold autoAb on ABO/Rh testing

A

Patients w/ strong cold agglutinins will have their own cells coated w/ autoAb (usually autoanti-I) and have spontaneous agglutination

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4
Q

Acquired B phenomenon

- Blood type that could demonstrate this reaction

A

Type A looks like an AB

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5
Q

Acquired B phenomenon

- In vitro reactions

A

Weak reaction w/ anti-B

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6
Q

Acquired B phenomenon

- Patient population

A

Often associated w/ disease or infection of digestive tract (i.e., colon cancer)

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7
Q

Acquired B phenomenon

- Type of blood to transfuse

A

?

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8
Q 
anti-A: 4+
anti-B: 0
anti-A,B: 4+
anti-A1 lectin: 4+
anti-H lectin: 0
Form anti-A1: No
Which subgroup of A is this?
A

A1

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9
Q 
anti-A: 4+
anti-B: 0
anti-A,B: 4+
anti-A1 lectin: 0
anti-H lectin: 3+
Form anti-A1: Yes
Which subgroup of A is this?
A

A2

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10
Q 
anti-A: 2+ (mf)
anti-B: 0
anti-A,B: 3+ (mf)
anti-A1 lectin: 0
anti-H lectin: 4+
Form anti-A1: Yes
Which subgroup of A is this?
A

A3

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11
Q 
anti-A: 0
anti-B: 0
anti-A,B: 2+
anti-A1 lectin: 0
anti-H lectin: 4+
Form anti-A1: Yes
Which subgroup of A is this?
A

Ax

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12
Q 
anti-A: 0
anti-B: 0
anti-A,B: 0
anti-A1 lectin: 0
anti-H lectin: 4+
Form anti-A1: Yes
Which subgroup of A is this?
A

Ael

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13
Q

Why do recent transfusions of “out-of-group” blood cause ABO discrepancies?

A

Causes mixed field reactivity

  • Exchange transfusions → remove patient’s blood and replace w/ donor blood
  • Fetal-maternal bleeding
  • A3 or B3 subgroups
  • Chimera (twins)
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14
Q

Explain how patient history can be used to resolve discrepancies fo mixed field reactivity seen in forward grouping

A

?

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15
Q

How does the age of a patient cause an ABO discrepancy?

A
  • Elderly people have depressed Ab production

- Newborns don’t make Abs until 3-6 months (any Abs seen are of maternal origin- Foward

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16
Q

Discrepancies of the forward typing

A
  • Extra reactivity
  • Weak/missing reactivity
  • Mixed field reactivity
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17
Q

Discrepancies of the reverse typing

A
  • Extra reactivity

- Weak/missing reactivity

18
Q

What could cause extra reactivity in the forward typing?

A
  • Rouleaux
  • Cold autoantibodies coating cells
  • Acquired B-like Ags
  • Polyagglutinable cells
19
Q

What could cause weak/missing reactivity in the forward typing?

A
  • Subgroups of A or B
20
Q

What could cause mixed field reactivity in the forward typing?

A
  • Recent transfusion w/ “out-of-group” blood
  • BM transplant
  • Exchange transfusions
  • Fetal-maternal bleeding
  • A3 or B3 subgroups
  • Chimeras
21
Q

Extra reactivity in forward typing → Rouleaux

- Lab findings

A

Appears as weak (loose) agglutination

- High proteins coat the cells and make them very sticky

22
Q

Extra reactivity in forward typing → Rouleaux

- Associated conditions

A
  • Multiple myeloma
  • Waldenstrom’s macroglobulinemia
  • Wharton’s jelly on cord blood samples
  • Plasma expanders (dextran and PVP)
23
Q

Extra reactivity in forward typing → Rouleaux

- Resolution

A
  • Wash patient’s cells 4-6x w/ saline; true agglutination washes away, rouleaux disappears; no agglutination on repeat testing
  • Cord blood samples need to be washed 4-6x before original testing b/c Wharton’s jelly causes spontaneous “agglutination”
24
Q

Extra reactivity in forward typing → Cold autoAbs

- Lab findings

A
  • Patients w/ strong cold agglutinins will have their own cells coated w/ autoAb (usually autoanti-I) and have spontaneous agglutination
25
Q

Extra reactivity in forward typing → Cold autoAbs

- Associated conditions

A
  • Mycoplasma pneumoniae → autoanti-I

- Cold hemagglutinin disease → autoanti-I

26
Q

Extra reactivity in forward typing → Cold autoAbs

- Resolution

A
  • Wash patient’s cells 4-6x w/ WARM saline

- Repeat ABO

27
Q

Extra reactivity in forward typing → Acquired B

- Lab findings

A
  • Group A looks like an AB (rxns w/ anti-B are usually weak)
  • Bacterial enzymes “eat away” the N-acteyl part of the group A sugar changing it into D-galactosamine, which cross-reacts w/ anti-B antisera
28
Q

Extra reactivity in forward typing → Acquired B

- Associated conditions

A

Colon cancer

29
Q

Extra reactivity in forward typing → Acquired B

- Resolution

A

Check patient’s diagnosis

30
Q

Extra reactivity in forward typing → Polyagglutination

- Lab findings

A
  • Patient’s cells have become T-activated (polyagglutinable) and react w/ all sources of human serum
31
Q

Extra reactivity in forward typing → Polyagglutination

- Resolution

A

Use monoclonal reagents (from mouse)

32
Q

Weak/missing reactivity in forward typing → subgroups of A or B
- Associated conditions

A
  • Leukemia

- Hodgkin’s disease

33
Q

Weak/missing reactivity in forward typing → subgroups of A or B
- Resolution

A
  • Check patient’s diagnosis
  • Anti-A1 lectin: only RBCs from A1 phenotype will agglutinate
  • Anti-H lectin: A1 cells will e weak or negative; other subgroups will be stronger (2+-4+)
  • Test w/ human anti-A,B: will be weakly reactive w/ subgroups of Ax and Bx (but negative w/ anti-A and/or anti-B)
  • Most sensitive tests, though rarely performed; adsorption/elution, secretor studies, serum transferase studies
34
Q

What could cause extra reactivity in the reverse typing?

A
  • Rouleaux
  • AutoAbs (I and/or H)
  • AlloAbs
35
Q

What could cause weak/missing reactivity in the reverse typing?

A
  • Age of the patient
  • Disease state
  • True chimera twins
36
Q

Extra reactivity in reverse typing → Rouleaux

- Resolution

A

Saline replacement technique

  • Set up usual reverse typing
  • Spin tubes
  • Take pipette and remove/discard plasma from each tube
  • “Replace” plasma in each tube w/ 2 drops saline
  • Spin and read
  • *True agglutination remains, rouleaux disappears
37
Q

Extra reactivity in reverse typing → AutoAbs

- Lab findings

A
  • If anti-I and/or anti-H are present, all screening cells will be positive at IS phase
38
Q

Extra reactivity in reverse typing → AutoAbs

- Resolution

A

Wash patient’s cells 4-6x w/ WARM saline; repeat ABO

39
Q

Extra reactivity in reverse typing → AlloAbs

- Lab findings

A
  • Anti-A, screening cells will be negative
  • Anti-M,N, P, Le seen at IS phase and Ab screen will be positive
  • Anti-Rh, K not seen at IS phase but Ab screen will be positive
40
Q

Extra reactivity in reverse typing → AlloAbs

- Resolution

A
  • Run ABID panel to prove the Ab 3+3
  • Ag type patient to prove they can make the Ab (should be Ag negative)
  • Repeat reverse typing w/ A1 and B cells that are negative for the Ag
41
Q

Weak/missing reactivity in reverse typing → Age of patient

- Resolution

A

Enhance reactivity of IgM Abs

  • ↑ serum: cell ratio
  • Incubate for 10-30’ @ RT
  • Incubate for 10-30’ @ 4C (must run AC or gorup O cells for negative control)
  • Use for enzyme0treated reverse cells
42
Q

Weak/missing reactivity in reverse typing → Disease state

- Associated conditions

A
  • Hypo- or agammaglobulinemia
  • Chronic lymphocytic leukemia (CLL)
  • Lymphomas; malignant lymphoma
  • Immunsuppressive drugs

Liz's Blood Bank Module 1 (10 decks)

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