Week 4

Question 1

What antigens are tested for on patient red cells in a Type and Screen?

Answer 1

A, B, and D antigens.

Question 2

Why would phenotyping be performed when antibodies are detected in a patient’s plasma?

Answer 2

To prove that the patient lacks the antigen on the red cells, confirming the presence of alloantibodies.

Question 3

Why is phenotyping important for multi-transfused patients, such as those with Sickle Cell or Thalassemia?

Answer 3

To provide antigen-negative blood to prevent antibody production in these patients.

Question 4

How do manufacturers contribute to the phenotyping process for antibody detection?

Answer 4

Manufacturers type donors to create screening panel cells used in antibody detection.

Question 5

In what non-clinical scenario might phenotyping be used?

Answer 5

Paternity testing.

Question 6

When should phenotyping be performed concerning recent transfusions?

Answer 6

Only perform phenotyping if the patient has NOT been transfused within the last 3 months (excluding ABO/Rh typing).

Question 7

Why would donor units be tested for a specific antigen in relation to the patient’s antibodies?

Answer 7

Donor units are tested for an antigen if the patient has developed an antibody and requires transfusions.

Question 8

When should donor units be tested for a previously identified antibody?

Answer 8

Test donor units if the patient has a history of a previously identified antibody.

Question 9

What is antiserum produced from?

Answer 9

Pools of serum from immunized individuals or monoclonal antibodies from hybridomas.

Question 10

How are monoclonal antibodies produced?

Answer 10

Monoclonal antibodies are produced from hybridomas, which are created by fusing antibody-forming cells with tumor cells.

Question 11

Who provides antiserum to hospitals and private labs?

Answer 11

Manufacturers provide antiserum to hospitals and private labs.

Question 12

What is the cost implication of obtaining antiserum for hospitals and labs?

Answer 12

Antiserum is provided at a very high cost.

Question 13

How do antibodies in antisera compare to antibodies in human serum/plasma?

Answer 13

Antibodies in antisera don’t always react the same as antibodies in human serum/plasma.

Question 14

How can antisera be manipulated?

Answer 14

Antisera can be monoclonal IgM or a polyclonal mixture of IgG and IgM.

Question 15

What are some IS IgM versions of antisera that exist?

Answer 15

IS IgM versions of Anti-K, Anti-S, and Anti-Jka exist, even though the patient would develop IgG versions.

Question 16

What mnemonic helps remember IgM antibodies in serum/plasma?

Answer 16

“ABBAPHILeMiN” helps remember IgM antibodies.

Question 17

What mnemonic helps remember IgG antibodies in serum/plasma?

Answer 17

“Duffy’S Kidds R OK” helps remember IgG antibodies.

Question 18

What are the variables in testing antisera that can influence the outcome?

Answer 18

Variables include using human source serum vs. monoclonal antibodies, different techniques (I.S., IAT, MTS), proportions (e.g., 1 drop 5% red cells + 2 drops antisera), incubation times, and centrifugation requirements.

Question 19

What are the key zones that affect antigen-antibody reactions in testing?

Answer 19

Pro-zone (excess antibody), Equivalence Zone (optimal antibody-antigen ratio), and Post-zone (excess antigen) are key zones affecting reactions.

Question 20

How do incubation times vary in antisera testing?

Answer 20

Incubation times vary based on the method used, with some requiring longer periods than others.

Question 21

Are all antisera testing methods the same in terms of cell handling?

Answer 21

No, some methods require centrifugation, while others may not and require the cells to sit at room temperature for 15 minutes and be gently resuspended.

Question 22

Why is washing the cells necessary in some techniques?

Answer 22

Washing removes unbound antibodies, preventing false positives or non-specific reactions in certain testing methods.

Question 23

How are the results and grading for ABO and D typing typically described?

Answer 23

Results and grading are generally strong.

Question 24

What built-in quality assurance feature exists in ABO typing?

Answer 24

The “forward and reverse” typing in ABO serves as built-in quality assurance (QA).

Question 25

What is the role of Anti-D1 and Anti-D2 in quality control?

Answer 25

Anti-D1 and Anti-D2 are used as a check for Rh typing accuracy.

Question 26

How frequently is quality control (QC) performed on ABO and Rh antisera in hospital or lab settings?

Answer 26

QC is performed daily on each antiserum rack.

Question 27

What is a key difference in quality control between ABO/Rh typing and other blood group phenotyping?

Answer 27

Other blood group phenotyping does not use reverse grouping (RA/RB) or a second antisera (D1/D2).

Question 28

How frequently is antisera used for other blood group phenotyping tested?

Answer 28

Antisera for other blood groups may not be tested for days or weeks.

Question 29

What controls must be run for other blood group (OBG) phenotyping?

Answer 29

Positive and negative controls must be run for OBG phenotyping.

Question 30

What type of cells are used for testing positive and negative controls in OBG phenotyping?

Answer 30

Manufacturer cells are used for testing because their phenotyping is known.

Question 31

What is required for a negative control in antiserum quality control?

Answer 31

The cells must lack the antigen.

Question 32

What is required for a positive control in antiserum quality control?

Answer 32

The cells must demonstrate the antigen in the weakest form (heterozygous cells).

Question 33

Why is using heterozygous cells important for positive controls in antiserum testing?

Answer 33

If the antiserum detects the weakest form of the antigen, it will certainly detect the strongest form.

Question 34

What type of cell is used for antigens with no alleles or silent alleles in positive phenotyping control?

Answer 34

Any antigen-positive cell can be used.

Question 35

What type of antigen expression is required for antigens with co-dominant alleles in positive phenotyping control?

Answer 35

Heterozygous expression of the antigen must be used.

Question 36

What does phenotyping indicate in blood testing?

Answer 36

Phenotyping indicates which antigens are present and is performed with serological testing.

Question 37

What does genotyping suggest in blood testing?

Answer 37

Genotyping suggests which genes are present according to the presence of antigens.