Question 1

When performing the elution procedure, the solution containing the recovered antibody is called:

Accepted Answer

The elution procedure is used to recover the antibody of interest from a solid support (such as a column or a plate) after it has been captured by an affinity reagent. The elution solution removes the antibody from the affinity reagent, and the resulting solution is called the eluate. Therefore, choice C is the correct answer. A, B, and D are not correct because they do not accurately describe the solution containing the recovered antibody.

Question 2

What is the purpose of Coombs' control cells?

Accepted Answer

Coombs' control cells are used to ensure that the AHG test is valid and reliable. They serve to check if washing has effectively removed any unbound antibody, to ensure that AHG was not omitted or inactivated, and to confirm that negative results are not false-negatives. Therefore, all of the options (A, B, C) are correct.

Question 3

In what test might rouleaux cause an interference?

Accepted Answer

C

Question 4

Routine pre-transfusion testing consists of all of the following except:

Accepted Answer

A Direct Antiglobulin Test (DAT) is not routinely performed as a part of pre-transfusion testing. It is performed only in certain circumstances like hemolytic transfusion reactions or suspected cases of hemolytic disease of the newborn. The routine tests in pre-transfusion testing are ABO typing, Rh typing, and an antibody screen to ensure compatibility between donor and recipient blood.

Question 5

All of the following antigens are found on reagent screening cells except:

Accepted Answer

Reagent screening cells do not typically express the Js^a antigen.

Question 6

The process of removing antibody from serum by combining a serum sample with appropriate red blood cells under optimal conditions is called:

Accepted Answer

This process is called absorption. Elution refers to the process of removing specifically bound antibodies from a solid phase, enzyme treatment refers to using enzymes to modify or cleave molecules, and sensitization refers to binding of an antibody to an antigen.

Question 7

How does LISS enhance antibody detection in the antibody screen?

Accepted Answer

LISS (low ionic strength solution) enhances antibody detection in the antibody screen by increasing the rate at which antibody binds to red blood cell antigens. This is achieved by reducing the ionic strength of the solution, which promotes better contact between the antibodies and the antigen sites on the red blood cells. As a result, the potency of weak antibodies is increased, and the sensitivity of the test is improved. Options A and B are incorrect, as LISS does not increase incubation times or zeta potential.

Question 8

Why is it important to match the lot number on the panel sheet with the lot number on the panel cells?

Accepted Answer

Matching the lot number on the panel sheet with the lot number on the panel cells is important to ensure consistency in the pattern of reactions. This is because different lots may have variations in their composition or manufacturing process, which can affect how the cells react with different antibodies. While ABO group can also change from lot to lot, this is less relevant in the context of matching lot numbers on panel sheets and cells. The FDA may have requirements for lot number tracking, but this is not necessarily the main reason why it is important to match lot numbers in this specific scenario.

Question 9

A patient with a warm autoantibody has a positive DAT. The antibody screen was negative, but the eluate reacted uniformly with all normal cells and patient cells. Why was the antibody screen negative?

Accepted Answer

The answer of A patient with a warm autoantibody has...

Question 10

What screening cells are used primarily for testing donor units for unexpected antibodies?

Accepted Answer

The answer of What screening cells are used primarily for...

Question 11

In interpreting an antibody screen, which of the following questions might be asked to decipher the class of antibody?

Accepted Answer

The phase in which the reaction occurs can help determine the class of the antibody. For example, IgM antibodies typically react at room temperature or in the cold, while IgG antibodies react at body temperature (37°C) and are often detected in the antiglobulin phase.

Question 12

Which of the following high-frequency antigens do not cause in vivo red blood cell destruction when complexed with corresponding antibody?

Accepted Answer

The answer of Which of the following high-frequency antigens do...

Question 13

Why is an enzyme treatment used in antibody identification?

Accepted Answer

Enzyme treatment is used in antibody identification to aid in the separation and identification of multiple antibodies and the absorption of autoantibody from patient serum. Enzymes such as papain, trypsin or ficin are used to digest the Fc portion of the antibody, leaving the Fab fragment intact. This allows for the identification of multiple antibodies present in a patient's serum by separating them based on their antigen specificity. Additionally, the enzyme treatment can be used to absorb any autoantibodies present in the patient's serum, which can interfere with the identification of specific antibodies. Thus, option D is the best choice as it encompasses both of the reasons for using enzyme treatment in antibody identification.

Question 14

Which of the following statements is correct concerning cold antibody screens?

Accepted Answer

Cold antibody screens are performed to detect the presence of cold-reactive antibodies in the patient's serum. The serum is incubated with adult and cord red blood cells of group O at 4°C.  This allows for the detection of antibodies that can cause agglutination or hemolysis of RBCs at lower temperatures typically found in the extremities, such as fingers and toes. Choice B is incorrect because cord cells are not typically used at 37°C as they lack certain antigens and their antibody expression may differ from adult cells. Choice C is incorrect because check cells are not used for antibody screening. Choice D is incorrect as group A cells are not typically used for antibody screening, and incubating at room temperature may not detect cold-reactive antibodies.

Question 15

What is an elution?

Accepted Answer

Elution is a technique used to dissociate IgG antibodies from sensitized RBCs. This is useful in blood banking when there is a need to identify the specificity of an antibody present in a patient's serum. By eluting the antibody from the sensitized RBCs, it can be tested and identified to select compatible blood for the patient. Elution is not used to dissociate IgM antibodies from sensitized RBCs or reduce the zeta potential enhancing antigen binding.

Question 16

Which cells are employed to remove autoantibody from patient serum without removing any alloantibody from serum?

Accepted Answer

Patient red blood cells are used to remove autoantibodies from the patient's serum because they have the same antigens as the autoantibodies, allowing for specific binding and removal, without affecting alloantibodies which are targeted against different antigens not present on the patient's cells.

Question 17

A positive autocontrol in antibody detection procedures is usually indicative of:

Accepted Answer

A positive autocontrol in antibody detection procedures typically indicates a positive direct antiglobulin test (DAT), suggesting the presence of antibodies or complement bound to the patient's red cells in vivo.

Question 18

What would be a realistic source of finding compatible units for a person with an antibody to a high-frequency antigen?

Accepted Answer

The answer of What would be a realistic source of...

Question 19

A person has developed an antibody to the LISS reagent. What test will not be affected by this circumstance?

Accepted Answer

The Direct Antiglobulin Test (DAT) is not affected by the presence of antibodies to LISS reagent. The other tests listed (Major ACT crossmatch, IAT, and Antibody screen) all use LISS reagent and would be impacted by the presence of LISS-specific antibodies.

Question 20

Which of the following statements concerning acid eluates is false?

Accepted Answer

The pH of the eluate is initially reduced to 3 or less, but it is then neutralized to around 7 for testing against a panel. Therefore, the statement that the pH of the eluate remains at 3 before testing against a panel is false.

Quiz 9: Detection and Identification of Antibodies