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12 Cards in this Set
- Front
- Back
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incomplete antibodies
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red cells sensitized with antibody but no agglutination is seen
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What are the components of Polyspecific Antihuman Globulin?
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Anti-IgG
Anti-C3 |
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Procedure for DAT.
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- red cells already sensitized with abs
- wash to remove unbound abs - AHG added; if bound abs present ---> agglutination --> (+) DAT if no bound abs --> (-) DAT |
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What are the 4 conditions in which DAT maybe used to detect sensitized rbcs?
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1. Autoimmune hemolytic anemia
2. Hemolytic disease of the Newborn 3. Delayed transfusion rxn 4. Sensitization of cell by drug complexes |
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Procedure for IAT.
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- red cells combined with antiserum
- incubate (allow sensitization) - wash unbound proteins - treat with anti-IgG - spin and read |
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What are checked cells?
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red cells sensitized with abs
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Why use check cells when there is a negative DAT/IAT result?
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- checked cells to confirm if AHG was added
- if added, should react with checked cells to agglutinate |
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What are some false positives for DAT/IAT?
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1. red cells are agglutinated before AHG is added, due to COLD REACTIVE AUTOANTIBODY
2. dirty glassware or tubes 3. over-centrifugation (clumping) |
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What are some false negatives for DAT/IAT?
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1. improper washing
2. delayed testing 3. loss of reagent activity 4. failure to see weak reactions 5. improper centrifugation 6. failure to add AHG 7. inappropriate red cell concentration |
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Why is antibody screen test done?
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to look for "unexpected" antibodies.
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What cell type are the screening cells?
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O
no antigens on surface |
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Why is EDTA specimen used when performing DAT?
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AHG will avoid in vitro activation of complement, only detect complement that was bound in vivo
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