Blood bank lab practical 1 material exam

ABO phenotype is determined by - ANSWER-both forward & reverse grouping Forward grouping is - ANSWER-using known sources of reagent antisera (antibodies) to detect antigens on the RBC Reverse grouping is - ANSWER-using reagent cells with known antigens & testing the plasma/serum for ABO antibodies The only Rh system antigen routinely tested for is - ANSWER-the D antigen, this is the 'pos' or 'neg' portion of typing The Rh control test is performed only on - ANSWER-AB pos blood, This must be a negative agglutination reaction for the AB pos to be valid. This test controls for spontaneous agglutination (false positives due to cold autoimmune disease or rouleaux) The concentration of RBCs in serological testing significantly affects - ANSWER-the accuracy Optimal concentrations for Master suspension are - ANSWER-3-5% (we use 4%) to reach the zone of equivalence Master suspension may be prepared in - ANSWER-in saline (85%), albumin or serum. Saline is most common & is the one we use Master suspension is used when - ANSWER-several drops of the same RBC suspension are needed for routine testing (ABO & Rh D forward, RBC antigen typing) Trouble shooting the master suspension cell color match - ANSWER-If the T cell button is much larger than the C, the suspension is too concentrated. Add more saline & repeat centrifugation & comparison If the T cell button is much smaller than the C, the suspension is too dilute. Add more cells to the suspension & repeat centrifugation & comparison. Potentiators are used to - ANSWER-enhance agglutination reactions. They adjust the test medium to promote the agglutination of antigen positive red cells by IgG antibodies. These IgG antibodies cannot span the normal distance between adjacent RBCs & demonstrate agglutination without the aid of a potentiator Potentiators are used in what tests - ANSWER-in antibody screen, antibody identification & cross-match tests