Blood Banking Immunology Review Questions with complete Solutions 100% Pass

Blood Banking Immunology Review Questions with complete Solutions 100% Pass What are blood group antigens? - Answers Most blood group antigens are proteins, glycoproteins, or glycolipids embedded in or protruding from the RBC membrane. Lewis antigens are exception. They are soluble substances in the plasma that are absorbed from plasma onto the RBC membrane. Antigens are also known as agglutinogens or immunogens. List several blood group antigens of low incidence. - Answers Cw, V, Kpa ,Jsa, Lua, M8, Vw, Dia, Wra, and Cob. These antigens are found in less than 1% of the population. List several high incidence blood group antigens. - Answers Kpb, k, Jsb, Lub, I, Ge, Tja, Vel, Yta, Dib, Coa, and U. These antigens are found in more than 99% of the population. What is the most common pattern of inheritance for blood group genes? - Answers Autosomal codominant. The genes are inherited equally by males and females and they are always expressed. For example, if one inherits the A and B genes, both A and B antigens are detected on the RBCs. Which RBC antigens are not fully expressed at birth? - Answers A, B, I, P1, Lewis and Lutheran. What is an antibody? - Answers An immunoglobulin that is produced in response to stimulation by a specific antigen and is capable of combining with the antigen that elicited its production. Antibodies are also known as agglutinins. They are found in the plasma and serum. What is an alloantibody? - Answers An antibody to a foreign antigen from someone of the same species. What is an autoantibody? - Answers An antibody to an antigen that one possesses. Autoantibodies are usually only produced in disease states. What is a naturally-occurring antibody? - Answers One that develops without known antigenic stimulus, for example, anti-A and anti-B. What is an immune antibody? - Answers One that results from exposure to a foreign red cell antigen through transfusion or pregnancy. If an untransfused male has an unexpected alloantibody, what type of antibody must it be? - Answers A naturally-occurring antibody. An untransfused male has not been exposed to foreign RBC antigens. What are high-titer, low-avidity blood group antibodies? - Answers Antibodies that cause weak, variable, and sometimes irreproducible reactions in the antiglobulin phase at high dilutions. They are not clinically significant. Example include anti-Ch, Rg, JMH, Csa, Kna, McCa, and Yka. Which immunoglobulin molecules are most frequently encountered in blood making? - Answers IgM and IgG. Compare the molecular structure of IgG and IgM and explain how their structure affects their reactivity in blood bank testing. - Answers IgG is a monomer. Because of its small size, it usually cannot agglutinate saline suspended RBCs. A potentiating medium or antiglobulin test is required. IgM is a pentamer. Because of its large size, it is a potent agglutinator, even of saline-suspended cells at room temperature, and it is an efficient activator of complement. Which class of immunoglobulins is destroyed by sulfhydryl compounds like 2-mercaptoethanol or dithiothreitol? - Answers IgM. These compounds break the J chains that hold IgM together. Which immunoglobulin class is most efficient at activating complement? - Answers IgM. Which immunoglobulin class can cross the placenta? - Answers IgG. What is sensitization? - Answers The attachment of antibodies to antigens on a red cell. List several factors that affect hemagglutination. - Answers The sensitization phase is affected by the temperature, the pH, the ionic strength of the medium, the antigen-antibody ratio, and the time of incubation. The agglutination phase is affected by the type of antibody, the density and location of antigens, and the zeta potential (electrostatic repulsion_. What are some potentiators that are used to enhance antigens-antibody reactions? - Answers 22% albumin, low ionic strength salt solution (LISS), and polyethylene glycol (PEG). What is the advantage of using LISS? - Answers It increases the rate at which an antibody binds to red cell antigens so the incubation time can be shortened to 10 minutes. What are two visible signs of antigen-antibody reaction in blood bank testing? - Answers Agglutinations and hemolysis. What causes hemolysis? - Answers The complement terminal membrane attack unit, C5b, C6, C7, C8, and C9. This unit embeds in the cell membrane and forms a hole. The loss of membrane integrity and the change in osmotic pressure within the cell leads to cell death and lysis. Explain the correct way to examine a tube for signs of an antigen-antibody reaction. - Answers Following centrifugation, the tube should be gently shaken or tilted until the cell button is completely dispersed. The manner in which cells come off the button should be observed. An optical aid, such as an agglutination viewer with a light and a magnifying mirror, should be used. In tube testing, how would three large agglutinates against a clear background be graded? - Answers 3+. In blood bank records, what must be recorded in addition to the degree of reactivity in all phase of testing? - Answers The interpretation of the reactions, the identity of the person who performed the tests, and the date of testing. Timely supervisor review is required. Why should serum separator tubes not be used in blood bank testing? - Answers The gel can