ABO Discrepancies Latest 2023 Already Passed

ABO Discrepancies Latest 2023 Already Passed discrepancy Red cell testing (forward type) does not match serum testing (reverse type) causes of discrepancy 1. weakened reaction strength 2. missing reaction 3. extra reaction 4. mixed field clerical errors mislabeling patient misidentification inaccurate interpretation transcription error computer error reagent and equipment errors uncalibration expired contaminated incorrect storage procedural errors incorrect concentrations button not resuspended reagent not added causes of clotting deficiencies 1. low platelet count 2. anticoagulant therapy 3. factor deficiencies fibrin clots developed if serum does not completely clot before testing mimics agglutination activation of clotting thrombin or EDTA tubes causes of hemolysis 1. complement binding 2. bacterial contamination reasons for missing or weak antigens in forward type 1. ABO subgroups 2. disease; leukemia, Hodgkins subgroups in forward type less antigen sites on RBCs cause weakened or missing reactions with antisera resolving subgroups in forward type test with anti-A1, anti-H, and anti-A1B for subgroups reasons for extra antigens in forward type 1. acquired B 2. B(A) phenotype 3. rouleaux 4. polyagglutination 5. whartons jelly acquired B in forward type caused by gut disease deacetylate group A1 sugar to form B sugar causes weak reaction with anti-B resolving acquired B test patients serum with own RBCs (own anti-B will not react with acquired B antigen) B(A) phenotype in forward type Group B patients with extra A antigen causes weak reaction with anti-A resolving B(A) test with another anti-A reagent from a different manufacturer polyagglutination in forward type agglutination with human antisera no matter what blood type due to bacterial infections or hidden T antigens wharton's jelly gelatinous substance found in cord blood that may cause false agglutination resolving wharton's jelly wash cells 5-6 times reasons for weak or missing antibodies in reverse type 1. age (newborns or elderly) 2. hypogammaglobulinemia 3. immunodeficiency 4. immunosuppressive drugs resolving weak/missing antibodies in reverse type 1. incubate 15 minutes at RT to enhance reaction 2. if still (-) incubate 5 minutes at 4C with autocontrol reasons for extra antibodies in reverse type 1. cold allo- or auto-antibodies 2. rouleaux 3. ABO subgroup (anti-A1) resolving cold antibodies in reverse type warm tube to 37C and wash red cells to disperse agglutination rouleaux increase of serum proteins (globulin) "stack of coins" appearance causes false agglutination strong reaction at immediate spin; weak at 37C; none at AHG assocations with rouleaux multiple meloma waldenstrom's macroglobulinemia hydroxyethyl starch resolving rouleaux remove proteins forward: wash cells reverse: saline replacement ABO subgroups/anti-A1 in reverse type A2 individuals can develop an anti-A1 resolving anti-A1 in reverse repeat reverse with A2 cells instead of A1 *should yield no agglutination bombay discrepancies causes no forward reaction and a positive reverse -test with anti-H lectin to determine if H is absent general rules for resolving discrepancies 1. always retest 2. check clerical and technical errors 3. check patients age, diagnosis, and history