ABO Discrepancies

Question 1

Forward type and reverse type not matching is known as what?

Answer 1

ABO discrepancy

Question 2

TRUE or FALSE:
ABORh testing is considered routine testing

Answer 2

TRUE

Question 3

Why is a reverse type not done on babies under 6 months old?

Answer 3

They have not formed antibodies yet

Question 4

TRUE or FALSE:
If forward and reverse types disagree, repeat BOTH

Answer 4

TRUE

Question 5

What are the 3 most common causes of ABO discrepancies?

Answer 5

-Reagents
-Wrong sample
-Testing errors

Question 6

TRUE or FALSE:
Clerical error is the #1 error in blood bank

Answer 6

TRUE

Question 7

Excess antibody

Answer 7

Prozone

Question 8

Excess antigen

Answer 8

Postzone

Question 9

Reasons reagents can cause a discrepancy (3)

Answer 9

-Wrong one used
-Expired or contaminated
-Omitted in testing

Question 10

Using the wrong concentration of cells can cause what result?

Answer 10

False negative

Question 11

Prozone and Postzone will give what result?

Answer 11

False negative

Question 12

Reasons wrong sample can cause a discrepancy (2)

Answer 12

-Wong patient sample used (patient not properly identified/sample mix up in lab)
-Specimen not handled or stored properly (left on tray for several hours or left at room temp for several days)

Question 13

Testing errors that can cause ABO discrepancy (7)

Answer 13

-Wrong temperature
-Wrong centrifugation
-Misinterpretation of a weak reaction or mixed field agglutination (mfa) as negative (overshaking)
-Failure to interpret hemolysis as a positive reaction
-Clerical errors in recording
-Tubes labeled incorrectly
-Over-reading - not shaking buttons off tube bottom

Question 14

Why is hemolysis considered a positive reaction in blood bank?

Answer 14

Complement activation

Question 15

Definition:
2 cell populations present

Answer 15

Mixed field agglutination

Question 16

Types of discrepancies (4)

Answer 16

-Forward discrepancy due to additional reactions or antigens
-Forward discrepancy due to missing antigens
-Reverse due to additional reactants or antibodies
-Reverse due to missing antibodies

Question 17

An inherited phenomenon primarily due to a genetic mutation that causes the sialic acid on RBC membranes to not be present and exposes a different antigen on the cell membrane (Tn antigen site).
-Occurs regardless of blood type
-will agglutinate everything

Answer 17

Polyagglutination

Question 18

Wharton’s jelly or rouleaux can cause this

Answer 18

Non-specific agglutination

Question 19

To avoid non-specific agglutination you should wash cells how many times?

Answer 19

4-8

Question 20

Name the ABO discrepancy:
-Usually occurs in type A1 patients
-Is due to intestinal obstruction or cancer

Answer 20

Acquired B

Question 21

Name the ABO discrepancy:
-Bacterial enzyme cleaves off the active group of A making it look like a B antigen and could react with B antisera

Answer 21

Acquired B

Question 22

TRUE or FALSE:
The protein in typing reagents can reduce the zeta potential enough to cause false reactions in sensitized red cells

Answer 22

TRUE

Question 23

Rare phenomenon between fraternal twins

Answer 23

Chimera-mixture of blood

Question 24

Name the ABO discrepancy

Answer 24

B (A) Phenotype

Question 25

Ways to resolve B (A) phenotype? (2)

Answer 25

-Test with additional monoclonal anti-A reagent by a different manufacturer -Use polyclonal human anti-A reagent

Question 26

Name the ABO discrepancy

Answer 26

Acquired B Phenotype

Question 27

Name the ABO discrepancy: -The B gene transfers trace amounts of N-acetylgalactosamine and D-galactose to the H antigen acceptor molecule -Increased sensitivity of reagent anti-sera causes the weak forward reaction with Anti-A

Answer 27

B(A) phenotype

Question 28

Name the ABO discrepancy: -Found in patients that have diseases of lower GI tract, cancers of colon, intestinal blockage, or infection with Gram Negative

Answer 28

Acquired B phenotype

Question 29

The following resolves what ABO discrepancy: -Test the patient's serum/plasma against autologous red blood cells -Test patient red cells with additional monoclonal anti-B reagents from another manufacturer that are documented not to react with the antigens associated with this discrepancy -Secretor studies (this ABO discrepancy will only have A substance in secretions)

Answer 29

Acquired B phenotype

Question 30

Name the ABO discrepancy:

Answer 30

Subgroup of A

Question 31

The following are resolutions for which ABO discrepancy: -Repeat red cell testing with extended incubation times -Include human polyclonal anti-A,B or monoclonal blend anti-A,B

Answer 31

Subgroup of a

Question 32

If a subgroup of A is suspected, what must be tested? (2)

Answer 32

A1 Lectin and A2 cells

Question 33

What plant does the A1 Lectin come from?

Answer 33

Dolichos biflorus

Question 34

A1 Lectin is ran in what part of ABO testing?

Answer 34

Front typing

Question 35

A2 cells will only agglutinate with which blood group types?

Answer 35

Group O and B

Question 36

Which subgroup of A is associated with a 2+ mixed-field agglutination reaction?

Answer 36

A3

Question 37

Name the ABO discrepancy: (Additional reactions/antibodies)

Answer 37

Rouleaux

Question 38

Rouleaux can be observed in which 2 diseases/disorders?

Answer 38

-Multiple Myeloma -Waldenstrom's Macroglobulinemia

Question 39

Name the ABO discrepancy: (additional reactions/antibodies)

Answer 39

Cold alloantibody

Question 40

The following would resolve which ABO discrepancy: -Test the patient's serum with screening cells and auto control at room temperature

Answer 40

Auto or Allo antibody

Question 41

Allo or Auto antibody

Answer 41

Cold auto antibody

Question 42

Allo or Auto antibody

Answer 42

Cold allo antibody

Question 43

When patient's serum is tested with his/her own red cells to determine whether an autoantibody is present

Answer 43

Autologous control aka Auto Control

Question 44

If you have positive reactions with A1, B, and screening cells - and the auto control is positive - what are you liking dealing with?

Answer 44

Cold autoantibody

Question 45

Most common discrepancy in a healthy individual?

Answer 45

Subgroups with Anti-A1

Question 46

Most frequent cause of weak or missing antibody (3)

Answer 46

-Babies -Elderly -Immunocompromised

Question 47

Optimum temperature for Anti-A and Anti-B

Answer 47

4C

Question 48

Name the ABO discrepancy:

Answer 48

Missing or Weak antibodies in serum testing

Question 49

The following will resolve which ABO discrepancy: -Determine patient's age and immunoglobulin level -Incubate serum testing for 15 minutes at room temperature, centrifuge, and examine -If room temperature incubation is still negative, place serum testing at 4C for 5 minutes with an autologous control

Answer 49

Missing or Weak antibodies in serum testing

Question 50

Interpret the following:

Answer 50

Cold autoantibody

Question 51

Interpret the following:

Answer 51

Group O

Question 52

Interpret the ABO result:

Answer 52

Normal A1

Question 53

Interpret the ABO result:

Answer 53

Normal A2

Question 54

Interpret the ABO result:

Answer 54

Normal B

Question 55

Interpret the ABO result:

Answer 55

Normal O

Question 56

Interpret the ABO result:

Answer 56

Normal A1B

Question 57

Interpret the ABO result:

Answer 57

Normal A2B

Question 58

Interpret the ABO result:

Answer 58

A2B with Anti-A1

Question 59

Interpret the ABO result:

Answer 59

A2 with Anti-A1

Question 60

Interpret the ABO result:

Answer 60

B with missing anti-A

Question 61

Interpret the ABO result:

Answer 61

A with acquired B antigen

Question 62

Interpret the ABO result:

Answer 62

O with rouleaux

Question 63

Interpret the ABO result:

Answer 63

Group B with cold autoantibody (Anti-I)

Question 64

Interpret the ABO result:

Answer 64

Group O infant

Question 65

Interpret the ABO result:

Answer 65

Bombay type

Question 66

Interpret the ABO result:

Answer 66

A with cold alloantibody

Question 67

Most common autoantibody

Answer 67

Anti-I