Blood Bank ASCP EXAM

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Blood Bank ASCP EXAM What type of serological testing does the blood bank technologist perform when determining the blood group of a patient? - ANS - phenotyping If anti-K reacts 3+ with a donor c ... ell with a genotype KK and 2+ with a Kk cell, the antibody is demonstrating: - ANS - 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? - ANS - Gender and Race. The frequency of Duffy antigens Fya and Fyb varies with race. The Fy(a−b−) phenotype occurs in almost 70% of African Americans and is very rare in whites. The Xga antigen is X-linked and, therefore, expressed more frequently in women (who may inherit the antigen from either parent) than in men. 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 - ANS - B. An individual with the BB genotype is homozygous for B antigen Which genotype is heterozygous for C? A. DCe/dce B. DCE/DCE C. Dce/dce D. DCE/dCe - ANS - A. DCe/dce Which genotype(s) will give rise to the Bombay phenotype? - ANS - The Bombay phenotype will be expressed only when no H substance is present. The Oh type is expressed by the genotype hh. Bombays produce naturally occurring anti-H, and their serum agglutinates group O red cells in addition to red cells from groups A, B, and AB persons. Meiosis in cell division is limited to the ova and sperm producing four gametes containing what complement of DNA? - ANS - 1N. Meiosis involves two nuclear divisions in succession resulting in four gametocytes each containing half the number of chromosomes found in somatic cells or 1N. A cell that is not actively dividing is said to be in: - ANS - Interphase, The cell is engaged in metabolic activity. Chromosomes are not clearly discerned; however, nucleoli may be visible Which of the following describes the expression of most blood group antigens? - ANS - Codominant What blood type is not possible for an offspring of an AO and BO mating? - ANS - 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? - ANS - - Indirect/secondary/second order An indirect/secondary/second order exclusion occurs when a genetic marker is absent in the child but should have been transmitted by the alleged father. In this case, either A or B should be present in the child. 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: - ANS - Linkage disequilibrium. Linkage disequilibrium is a phenomenon in which alleles situated in close proximity on a chromosome associate with one another more than would be expected from individual allelic frequencies. 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. - ANS - Autosomal Dominant In the Hardy-Weinberg formula, p2 represents: - ANS - In the Hardy-Weinberg formula p2 + 2pq + q2, p2 and q2 represent homozygous expressions and 2pq represents heterozygous expression. This formula is used in population genetics to determine the frequency of different alleles. What is the Hardy-Weinberg formula? - ANS - p2 + 2pq + q2 = 1 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? - ANS - 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? - ANS - LISS. LISS contains a reduced concentration of NaCl (0.2%) and results in a reduction in charged ions within the ionic cloud, decreasing the zeta potential and facilitating antigen and antibody interaction. This type of antibody response is analogous to an anamnestic antibody reaction. - ANS - Secondary. An anamnestic response is a secondary immune response in which memory lymphocytes respond rapidly to foreign antigen in producing specific antibody. The antibodies are IgG and are produced at lower doses of antigen than in the primary response. Which antibodies to a component of complement are contained in the rabbit polyspecific antihuman globulin reagent for detection of in vivo sensitization? - ANS - In the DAT (direct antiglobulin test), rabbit polyspecific antisera contains both an anti-human IgG component and an antibody against the C3d component of complement. Which of the following distinguishes A1 from A2 blood groups? A. A2 antigen will not react with anti-A, A1 will react strongly (4+) B. An A2 person may form anti-A1; an A1 person will not form anti-A1 C. An A1 person may form anti-A2, an A2 person will not form anti-A1 D. A2 antigen will not react with anti-A from a nonimmunized donor; A1 will react with any anti-A - ANS - B. 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 antiH lectin. What is the most likely cause of these results? - ANS - Bombay is the only ABO phenotype incompatible with O cells. The red cells of a Bombay show a negative reaction to anti-H because the cells contain no H substance What antibodies are forme [Show More]

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