ABO Discrepancy Quiz and Flashcards (PDF Included)

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Questions and Answers

What is the primary reason for testing an auto control and O cell control concurrently with reverse typing?

To confirm the accuracy of ABO typing.

To detect cold agglutinins that enhance reactivity. (correct)

To identify minor ABO incompatibility.

To prevent hemolysis during infusion.

What characteristic feature may appear in a mixed-field agglutination?

A uniform color change in the test medium.

A consistent clumping of all RBCs.

A clear zone of unagglutinated cells.

A halo effect of unagglutinated RBCs. (correct)

What complication is associated with major ABO incompatibility?

Allergic reactions during transfusion.

Increased leukocyte count.

Hemolysis of RBCs at the time of infusion. (correct)

Resistance to blood type changes.

Which type of incompatibility is described when the donor’s plasma is incompatible with the recipient’s RBCs?

Minor ABO incompatibility. Signup and view all the answers

What unique challenge do transfusion services face post-ABO incompatible HPC transplantation?

Compatibility of blood products with both donor and recipient types. Signup and view all the answers

What remains in the tissues of a patient following an ABO-incompatible HPC transplant?

The pre-transplant ABO type for their lifetime. Signup and view all the answers

What does chimerism refer to in a medical context?

Presence of two genetically different cell populations in an individual. Signup and view all the answers

What can cause mixed-field reactions in blood typing?

Receiving non-ABO type specific RBCs. Signup and view all the answers

What factor primarily causes an extra-positive reaction in ABO discrepancies?

Presence of unexpected antibodies in the serum Signup and view all the answers

Which of the following is NOT a technical error that can lead to ABO discrepancies?

Inadequate patient history review Signup and view all the answers

What is the first step that should be taken to resolve most technical errors in ABO discrepancy testing?

Use a saline suspension of RBCs for retesting Signup and view all the answers

Which statement correctly describes forward grouping?

Detecting antigens on an individual's RBCs using antisera Signup and view all the answers

Which technical error could most likely lead to false-negative results during ABO grouping?

Omitting the addition of reagents Signup and view all the answers

What key factor must be checked when resolving an ABO discrepancy if a clerical error is suspected?

Identification of blood specimens and test tubes Signup and view all the answers

In forward grouping, which antisera is used to detect the presence of B antigens?

Anti-B serum Signup and view all the answers

Which of the following actions is recommended to avoid reagent contamination during testing?

Adding serum and antiserum first Signup and view all the answers

What is the primary reason that true chimerism is rarely found in individuals?

It is limited to specific genetic conditions in multiple births. Signup and view all the answers

Which of the following correctly identifies a scenario for artificial chimerism?

A patient receiving group O blood transfusion. Signup and view all the answers

What causes Group II Discrepancies in blood grouping?

Weakly reacting or missing antigens. Signup and view all the answers

How can weakly reactive antigens be detected more effectively during testing?

By incubating at room temperature for an extended duration. Signup and view all the answers

What phenomenon can result in weak reactions with anti-B antisera?

Acquired B phenomenon associated with digestive tract diseases. Signup and view all the answers

Which factor does NOT contribute to the emergence of mixed cell populations in artificial chimeras?

In utero blood exchange. Signup and view all the answers

What occurs as a result of vascular anastomosis during twin pregnancies?

Formation of distinct cell populations recognized as self. Signup and view all the answers

Which situation would most likely lead to a Group II Discrepancy in blood typing?

A patient undergoing chemotherapy. Signup and view all the answers

What is a typical characteristic of the forward grouping reaction with B antigen?

It often results in mixed-field agglutination. Signup and view all the answers

What causes the ABO discrepancy in the reverse grouping of cis-AB individuals?

Weak anti-B antibodies in the serum. Signup and view all the answers

Which phenomenon can result from unequal crossing over between A and B genes in cis-AB individuals?

Production of an enzyme that transfers both A and B sugars. Signup and view all the answers

Which of the following examples represents a technical error leading to an ABO discrepancy?

Incorrect cell suspension density. Signup and view all the answers

What is likely indicated by an ABO type showing 4+ with Anti-A, 4+ with Anti-B, and 2+ with A1 cells?

Possibility of an enzyme mutation at the ABO locus. Signup and view all the answers

In individuals with the Acquired B phenomenon, which reaction is typically observed?

Weak reactivity with B cells. Signup and view all the answers

What enzyme deficiency is commonly noted in cis-AB individuals compared to ordinary group AB sera?

Decreased B transferase. Signup and view all the answers

What disorder may manifest through an extra positive reaction in reverse grouping with negative autocontrol?

Cold alloantibodies. Signup and view all the answers

What modification leads to the formation of the pseudo-B antigen in the acquired B phenomenon?

Alteration of N-acetylD-galactosamine into D-galactosamine Signup and view all the answers

What effect does lowering the pH of reagents containing monoclonal anti-B clone (ES4) have on the agglutination reaction?

Facilitates strong agglutination of cells with the acquired B antigen Signup and view all the answers

Why does testing the patient's serum or plasma against autologous RBCs yield a negative reaction in the acquired B phenomenon?

Patient’s RBCs with acquired B antigen cannot agglutinate due to lack of reaction Signup and view all the answers

Which of the following factors does NOT affect the agglutination of acquired B antigen when reacting with anti-B?

Temperature of the reaction exceeding 37 degrees Celsius Signup and view all the answers

What is the consequence of excessive amounts of blood group–specific soluble substances in a patient's plasma?

Neutralization of the reagent anti-A or anti-B leading to weak or false-negative results Signup and view all the answers

What is the expected outcome when treating RBCs with acetic anhydride in the context of acquired B phenomenon?

Reduces the reactivity with anti-B while leaving normal B cells unaffected Signup and view all the answers

What is the significance of secretor studies in the context of the acquired B phenomenon?

Assessing the presence of A substance secretion in the patient Signup and view all the answers

Which of the following best describes low-prevalence antibody reactions in relation to anti-A or anti-B reagents?

They can lead to weakly reactive or missing reactions by binding with corresponding low-prevalence antigens Signup and view all the answers

Study Notes

ABO Blood Group Discrepancies

ABO discrepancies arise when unexpected results occur in forward or reverse blood grouping.
Potential causes include issues with the patient's serum, RBCs, or both.
Discrepancies manifest as extra-positive, weak, or missing reactions.

Grouping Definitions

Forward grouping detects RBC antigens using commercial antisera (anti-A, anti-B) on patient RBCs.
Reverse grouping identifies ABO antibodies in patient serum using known reagent RBCs (A1 and B cells).

Technical Errors Leading to Discrepancies

Clerical Errors: Inaccurate identification of blood specimens can lead to discrepancies.
Sample Errors: Mix-ups or missed observations such as hemolysis may occur.
Reagent Issues: Expired or contaminated reagents can impact results.
Instrument Problems: Use of uncalibrated centrifuges may yield inaccuracies.
Procedure Errors: Inadequate sample preparation, such as incorrect cell suspension density or failure to follow instructions, can lead to errors.

Resolving Technical Errors

Retesting with saline suspensions can eliminate some issues caused by sample problems.
Review patient history for age, diagnosis, and transfusion records is essential.
Concurrent testing with auto controls and O cell controls is recommended to detect common cold agglutinins.

Major and Minor ABO Incompatibilities

Major Incompatibility: Occurs when donor RBCs are incompatible with recipient plasma (e.g., group B donor and group O recipient).
Minor Incompatibility: Occurs when donor plasma reacts against recipient RBCs (e.g., group O donor with anti-B plasma and group B recipient).
Bidirectional Incompatibility: Presence of both major and minor incompatibility types.

Chimerism

Chimerism refers to the presence of two distinct cell populations in one individual, often identified in twins.
True chimerism arises from in utero blood exchange, allowing both populations to coexist without antibody formation.

Group II Discrepancies

May result from weakly reacting or missing antigens, often occurring with blood group subgroups or in conditions like leukemia.
Acquired B phenomenon alters A antigen structure, resulting in weak reactions with anti-B antisera, often due to digestive tract diseases.

Resolution Strategies for Group II Discrepancies

Enhancing agglutination of weakly reactive antigens through incubation at room temperature or cold temperatures.
Testing against controls and considering enzyme pretreatment of RBCs.
The acquired B phenomenon can be resolved with specific monoclonal antibodies (ES4) or by lowering reagent pH.

Rare Group II Discrepancies

May be caused by excess soluble blood group substances in plasma or antibodies to low-prevalence antigens.
Some individuals, such as those with cis-AB, showcase unique antigen patterns that complicate standard grouping.

Key Notes

Continuous monitoring and adherence to strict protocols prevent inconsistencies in blood typing.
Blood components must be compatible with both donor and recipient blood types during transfusions to prevent serious complications.

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Description

Test your knowledge about ABO blood group discrepancies, including their causes and the methods used for forward and reverse grouping. Understand the technical errors that can lead to unexpected results in blood typing and the importance of accurate procedures. This quiz is essential for those interested in hematology and blood bank practices.

ABO Blood Group Discrepancies Quiz

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