2024 Harr Medical Laboratory Science // Harr ASCP Review Harr – Immunology QUESTION AND CORRECT SOLUTION 100% GUARANTEE PASS

What type of serological testing does the blood bank technologist perform when determining the blood group of a patient? - ANSWER Phenotyping If anti-K reacts 3+ with a donor cell with a genotype KK and 2+ with a Kk cell, the antibody is demonstrating: - ANSWER Dosage Carla expresses the blood group antigens Fya, Fyb ,and Xga. James shows expressions of none of these antigens. What factor(s) may account for the absence of these antigens in James? - ANSWER Gender and race Which of the following statements is true? a. An individual with the BO genotype is homozygous for B antigen b. An individual with the BB genotype is homozygous for B antigen c. An individual with the OO genotype is heterozygous for O antigen d. An individual with the AB phenotype is homozygous for A and B antigens - ANSWER An individual with the BB genotype is homozygous for B antigen Which genotype is heterozygous for C? - ANSWER DCe/dce Which genotype(s) will give rise to the Bombay phenotype? - ANSWER hh only Meiosis in cell division is limited to the ova and sperm producing four gametes containing what complement of DNA? - ANSWER 1N A cell that is not actively dividing is said to be in: - ANSWER Interphase Which of the following describes the expression of most blood group antigens? - ANSWER Codominant What blood type is not possible for an offspring of an AO and BO mating? - ANSWER All are possible The alleged father of a child in a disputed case of paternity is blood group AB. The mother is group O and the child is group O. What type of exclusion is this? - ANSWER Indirect/secondary/second order If the frequency of gene Y is 0.4 and the frequency of gene Z is 0.5, one would expect that they should occur together 0.2 (20%) of the time. In actuality,they are found together 32% of the time. This is an example of: - ANSWER Linkage disequilibrium In the Hardy-Weinberg formula, p^2 represents: - ANSWER The homozygous population of one allele In this type of inheritance, the father carries the trait on his X chromosome. He has no sons with the trait because he passed his Y chromosome to his sons; however, all his daughters will express the trait. - ANSWER X-linked dominant Why do IgM antibodies, such as those formed against the ABO antigens, have the ability to directly agglutinate red blood cells (RBCs) and cause visible agglutination? - ANSWER IgM antibodies are larger molecules and have the ability to bind more antigen Which of the following enhancement mediums decreases the zeta potential, allowing antibody and antigen to come closer together? - ANSWER LISS This type of antibody response is analogous to an anamnestic antibody reaction. - ANSWER Secondary Which antibodies to a component of complement are contained in the rabbit polyspecific antihuman globulin reagent for detection of in vivo sensitization? - ANSWER Anti-IgG and anti-C3d Which of the following distinguishes A1 from A2 blood groups? - ANSWER An A2 person may form anti-A1; an A1 person will not form anti-A1 A patient's serum is incompatible with O cells. The patient RBCs give a negative reaction to anti-H lectin. What is the most likely cause of these results? - ANSWER The patient may be a Bombay What antibodies are formed by a Bombay individual? - ANSWER Anti-A, B, and H Acquired B antigens have been found in: - ANSWER Group A persons Blood is crossmatched on an A positive person with a negative antibody screen. The patient received a transfusion of A positive RBCs 3 years ago. The donors chosen for crossmatch were A positive. The crossmatch was run on the Ortho Provue and yielded 3+ incompatibility. How can these results be explained? - ANSWER The patient is an A2 with anti-A1 A patient's red cells forward as group O, serum agglutinates B cells (4+) only. Your next step would be: - ANSWER Incubate washed red cells with anti-A1 and anti-A,B for 30 minutes at room temperature Which typing results are most likely to occur when a patient has an acquired B antigen? - ANSWER Anti-A 4+, anti-B 1+, A1 cells neg, B cells 4+ Which blood group has the least amount of H antigen? - ANSWER A1B What type RBCs can be transfused to an A2 person with anti-A1? - ANSWER A or O What should be done if all forward and reverse ABO results as well as the autocontrol are positive? - ANSWER Wash the cells with warm saline, autoadsorb the serum at 4°C What should be done if all forward and reverse ABO results are negative? - ANSWER Incubate at 22°C or 4°C to enhance weak expression N-acetyl-D-galactosamine is the immunodominant carbohydrate that reacts with: - ANSWER Dolichos biflorus A stem cell transplant patient was retyped when she was transferred from another hospital. What is the most likely cause of the following results? Patient cells: Anti-A, neg; Anti-B, 4+ Patient serum: A1 cells, neg; B cells, neg - ANSWER Immunodeficiency What reaction would be the same for an A1 and an A2 person? - ANSWER Positive reaction with anti-A,B A female patient at 28 weeks' gestation yields the following results: Patient cells: Anti-A 3+; Anti-B 4+ Patient serum: A1 cells, neg; B cells 1+; O cells, 1+ - ANSWER Alloantibody in patient serum Which condition would most likely be responsible for the following typing results? Patient cells: Anti-A, neg; Anti-B, neg Patient serum: A1 cells, neg; B cells, 4+ - ANSWER Weak or excessive antigen(s) Which of the following results is most likely discrepant? Anti-A, neg; Anti-B, 4+ A1 cells, neg; B cells, neg - ANSWER Negative A1 cells A 61-year-old male with a history of multiple myeloma had a stem cell transplant 3 years ago. The donor was O positive and the recipient was B positive. He is admitted to a community hospital for fatigue and nausea. Typing results reveal the following: Anti-A = 0; Anti-B =0; Anti-A,B = 0; Anti-D = 4+; A1 cells = 4+; B cells = 0 How would you report this type? - ANSWER Undetermined A complete Rh typing for antigens C, c, D, E, and e revealed negative results for C, D, and E. How is the individual designated? - ANSWER Rh negative How is an individual with genotype Dce/dce classified? - ANSWER Rh positive If a patient has a positive direct antiglobulin test, should you perform a weak D test on the cells? - ANSWER No, the cells are already coated with antibody Which donor unit is selected for a recipient with anti-c? - ANSWER r'ry Which genotype usually shows the strongest reaction with anti-D? - ANSWER D-/D- Why is testing for Rh antigens and antibodies different from ABO testing? a. ABO reactions are primarily due to IgM antibodies and usually occur at room temperature; Rh antibodies are IgG and agglutination usually requires a 37°C incubation and enhancement media b. ABO antigens are attached to receptors on the outside of the red cell and do not require any special enhancement for testing; Rh antigens are loosely attached to the red cell membrane and require enhancement for detection c. Both ABO and Rh antigens and antibodies have similar structures, but Rh antibodies are configured so that special techniques are needed to facilitate binding to Rh antigens d. There is no difference in ABO and Rh testing; both may be conducted at room temperature with no special enhancement needed for reaction - ANSWER ABO reactions are primarily due to IgM antibodies and usually occur at room temperature; Rh antibodies are IgG and agglutination usually requires a 37°C incubation and enhancement media Testing reveals a weak D that reacts 1+ after indirect antiglobulin testing (IAT). How is this result classified? - ANSWER Rh positive