ABO Grouping Discrepancies Quiz

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Questions and Answers

Explain the conditions under which a patient might exhibit weak ABO antigen expression, besides the presence of subgroups.

Weak ABO antigen expression can occur in conditions like acute leukemias where the red cell antigens in the ABO system may be greatly depressed, leading to weak reactions. Additionally, blood group-specific substances, such as those found in ovarian cysts and carcinomas, can neutralize anti-A and anti-B antibodies, resulting in weak reactions when unwashed cells are used.

What are the potential causes of a discrepancy in ABO blood grouping due to missing or weak antibodies?

Missing or weak antibodies can be caused by factors such as the patient's age (infants or elderly), hypogamaglobulininemia (due to conditions like lymphomas, leukemia), or the use of immunosuppressive drugs. These conditions can affect the production or presence of antibodies.

Describe the mechanism by which acquired B antigen occurs in patients with blood group A or O.

Acquired B antigen is a phenomenon where bacterial enzymes or absorbed bacterial polysaccharides alter the red cells of group A or O patients, resulting in weak B antigen reactions in the forward grouping. This is due to the acquisition of B specificity through the interaction with these bacterial components.

Identify the potential sources of technical errors that can contribute to ABO blood grouping discrepancies and how they might be resolved.

Technical errors include contaminated reagents or glassware, incorrect centrifugation speeds or ratios, improper incubation temperatures, and failure to add necessary specimens or reagents. These can be resolved by meticulous attention to details, proper technique adherence, and repeating the test procedures with careful controls. Signup and view all the answers

Explain what steps can be taken to enhance reactions in reverse ABO grouping when dealing with weak antibodies.

Enhancing reactions in reverse ABO grouping can be achieved by prolonging the incubation time of the patient's serum with red cells at room temperature (15 minutes) or by incubating at lower temperatures (5°C or 4°C). These modifications can facilitate antibody-antigen binding and improve detection. Signup and view all the answers

Discuss the significance of blood group specific substances in causing ABO blood grouping discrepancies.

Blood group-specific substances, commonly found in ovarian cysts and carcinomas, can bind to and neutralize anti-A and anti-B antibodies. This neutralization can lead to false-negative results in ABO grouping, especially when unwashed cells are used. Signup and view all the answers

Describe the impact of acriflavin, a dye used in some commercial anti-B reagents, on ABO blood grouping.

Acriflavin, a yellow dye used in some anti-B reagents, can cause false agglutination in certain individuals. This is because antibodies against acriflavin in the serum can combine with the dye and attach to the individual's erythrocytes, leading to false-positive results. Signup and view all the answers

Explain the rationale behind repeating ABO blood grouping tests if careful controlled testing yields the same agglutination patterns.

If carefully controlled repeat testing yields the same agglutination patterns, the variation can be assigned to one of the four categories: missing or weak antibodies, missing or weak antigens, acquired B antigen, or a combination of these factors. Repeating the test ensures that the observed pattern is not due to technical errors and allows for a confident assignment of the cause of the discrepancy. Signup and view all the answers

Flashcards

ABO grouping discrepancies

Differences in erythrocyte and serum results during blood typing.

Technical errors

Mistakes during ABO testing often due to equipment or reagents.