6. ABO and Rh Discrepancies Flashcards Preview

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Flashcards in 6. ABO and Rh Discrepancies Deck (25):
1

Other 'A' subgroups all have ________ reaction when tested w/ commerical anti-A or anti-A,B reagents

weak or no

2

Minimum rxn w/ anti-D for Rh POS?

2+

3

Most common ABO discrepancy?

No reverse typing rxns

4

May be seen in bone marrow or transplant recipients

Mixed field

5

4 'B' subgroups

B3, Bx, Bm, Bel

6

What reagent is used to distinguish A1 from A2 red cells?

Dolichos biflorus lectin (anti-A1)

7

Strong rxn w/ _____ proves that it is not Bombay phenotype

anti-H

8

2 possible causes of additional antibodies in serum/plasma?

Rouleaux
Cold autoantibody

9

Reasons for A1 reverse reacting positively discrepancy?

Probable A2 subgroup with anti-A1

10

Anti-H lectin

Ulex europaeus

11

% of A1 and A2 individuals?

80% A1 or A1B
20% A2 or A2B

12

Cause of B(A) phenotype

Group B individuals have trace amounts of A antigen

13

What change causes acquired B phenotype?

Bacterial enzyme alters A sugar to resemble B sugar = cross-rxn

14

This subgroup has strong agglutination reactions w/ anti-H

Other A subgroups (A3,Ax, Aend, Am, Ay, Ael)

15

How to resolve a positive Rh control?

Repeat w/ washed patient cells

Perform DAT

16

Most likely reason for no reverse typing rxns?

Patient - old age

17

Why does A2 subgroup have less A antigen than A1?

A2 gene's transferase is less efficient at converting H to A substance

18

Associated w/ multiple myeloma and Waldenstrom's macroglobulinemia

Rouleaux

19

Seen in group A1 individuals with diseases of the lower GI tract, Ca of the
colon or rectum, intestinal obstruction, or gram-neg septicemia

Acquired B phenotype

20

What are ABO subgroups?

Phenotypes that show weaker variable serological reactivity with the commonly used human polyclonal Anti-A, Anti-B, and Anti-A,B reagents

21

Subgroup suggested by seeing mixed field

A3

22

What characterizes mixed field rxns?

Fwd grouping is weak and mixed field; reverse is fine

23

What is used to agglutinate B cells?

Bandeiraea simplicofolia (anti-B)

24

Resolution for cold autoantibody or alloantibodiy

Perform antibody screen w/ autocontrol

25

Resolution for rouleaux discrepancy

Saline replacement