Transfusions Flashcards
Indirect Coombs test or AHG
test if have an antibody; take patient serum/plasma and add to donor RBC antigen; Add anti_human globulin to cause precipitation or agglutination
Direct Coombs test
detects antibodies coating patient RBC in vivo; Add anti-human globulin to already coated RBC (with IgG or C3); Agglutination will occur
Carbohydrate group (ABO, H, Lewis, I and P blood groups)
Requires glycosyl transferases to synthesize antigens
ABO antibodies
naturally occurring, enterobacteriacae possesses ABO like structure on lipopolysaccharide coats
Frequency of blood types
45% blood type O; 40% blood type A; 11% blood type B; 4% blood type AB
Bombay phenotype
total lack of H, A, and B antigens due to lack of H and secretor genes; Antibody screen wildly positive and all units incompatible
Children are i
associated with chronic hemolytic disorders, anti-i in infectious mononucleosis
Adults (older than 2) are I
anti-I associated with Cold Hemagglutinin Disease (CHAD) and Mycoplasma Pneumonia
P1 antigen
Receptor for Parvo Virus B19 (sickle cell, myelosuppression); Anti-P associated with Paroxysmal cold hemoglobinuria (PCH), Hydatid cyst, and in bird handlers
LeB (Lewis B antigen)
receptor for H. pylori
Rh antibodies
5 major antigens: D, C, E, c, e; immunogenecity D > c > E
Weak D
quantitative defect in D antigen, D antigen is normal, no antibodies formed
Partial D
qualitative defect in D antigen, abnormal form leading to alternation of exterior part of the antigen -> antibodies formed against absent parts of RhD; anti-D in D-positive person; Partial D mom need Rhogam
Hemolytic Disease of fetus and new born (HDFN)
Anti-D (IgG) from sensitized mother crosses placenta to bind to baby Rh+ RBC causing fetal destruction followed by anemia, erythroblastosis, hydrops, rising bilirubin (kernicterus)
Rosette test
qualitative test for fetal bleed in the mother; Treat mother_s RBCs with anti-D. Fetal RBC binds with anti-D and other Rh+ RBCs form a rosette around it.
Kleihauer betke test
quantitative test for fetal bleed in the mother; Acid denatures HbA but HbF is resistant. Count resistant (non-ghost) cells.
U antigen
Very prevalent, but if a person is U- then they must get blood from a U- person because of hemolysis. Need to go to red donor registry to obtain the blood, takes time to get from frozen inventory.
McLeod phenotype/syndrome
exclusive in males, hemolytic anemia with acanthocytes; Kx and Km absent, all other Kell Ags markedly decreased but not absent
Duffy system
Fy (a-b-) is most common in African-Americans (68%; even higher in Africa); resistant to malaria but suspectible to prostate cancer (normal glycoprotein clears chemokines)
Kidd system
Severe acute HTRs possible, marked dosage effect, mild HDFN; antibodies disappear over time, important to get and note patient_s history
