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PathofBloodGroups
lecture 15 sutor
Question | Answer |
---|---|
6 blood cell groups of greatest clinical significance | ABO, Rh (C, c, D, E, e), Duffy (Fy-a, Fy-b), Kidd (Jk-a, Jk-b), Kell (K, k), MNSs (S, s most important) |
autoantibody | Ab is produced due to some dysregulation of pt's immune system, they attack Ag in pt's own body |
alloantibody | Ab produced against some foreign cell or substance that enters pt's body |
most immunogenic blood group antigen | Rh-D |
blood group antigen most likely to cause Ab formation | K of Kell |
red cell alloantibodies of clinical significance are virtually always of the _______ class EXCEPT anti-A/B, which are of the _______ class | alloantibodies like Rh, Duffy, etc - usually IgG /// anti-A and anti-B are usually IgM |
which blood group interaction cause immediate intravascular hemolysis that usually results in death | ABO blood group incompatibilities |
anti-A/B antibodies in O blood type pt are of what Ig class? | O-type pts make IgG class Abs, NOT IgM |
delayed type hemolytic rxns | usually occur from IgG class Abs like those in pts with O type blood or from Kidd Ag, cause extravascular hemolysis hours to days after transfusion, progressive anemia fever and discomfort noted |
situations in which hemolytic dz of the newborn occurs | mismatch in blood groups btwn mom and fetus with baby having at least one Ag mom doesn't, mother has made Ab previously, any IgG Ab that can cross placenta, any Ab that destructs fetal RBCs |
blood type in mother that would be most concerning for hemolytic dz of newborn | O --> she has pre-formed anti-A/B/AB of the IgG type that can cross the placenta |
indirect antiglobulin test | done with type and screen, looks for free RBC antibody in pt's plasma or serum. indicated for routine preg screening or work-up of autoimmune hemolysis |
direct antiglobulin test (formerly the direct Coombs' test) | will be (+) when either Ig or complement is actually bound to circulating RBCs of pt; ordered when immune hemolysis is suspected, for work-up of transfusion rxn, newborn infants with jaundice, work-up of anemia with unk cause |
7 days after blood transfusion pts with no immunosuppression are likely to develop Abs to Rh | thus pre-formed Abs wouldn't have been detected for initial transfusion, but if they are given blood with the same Rh subtype there will be an ANAMNESTIC RESPONSE where on 2nd exposure Ab production is ramped up quickly = delayed hemolytic transfusion rxn |