TM Rh Group Flashcards
Fisher-Race Theory
- Rh Blood Group = closely linked loci where crossing over does not occur (CDE)
- besides the D antigen, there are C, c, E, e antigens
Describe Rh antigens
- polypeptides
- on amphiphilic protein that weaves back and forth through the cell’s membrane
Characteristics of Rh antibodies
- IgG; clinically significant
- Dosage
- Enzyme-enhanced
CDe
R¹
cDE
R²
cDe
R⁰
CDE
Rᶻ
Cde
r’
cdE
r”
cde
r
CdE
rʸ
Describe Rh null individuals
- no Rh antigens (___/___)
- inherited two copies of amorphic gene OR a suppressor gene = inhibits patient from expressing antigens
- have mild, compensated hemolytic anemia
Differentiate genetic weak D vs partial D
Genetic weak D:
- most D antigens inside RBC
- difficult for anti-D to access
Partial weak D:
- “mosaic” antigen is missing a piece
- anti-D will not bind to altered epitope during testing = FALSE Rh-
- if patient is given Rh pos blood, patient can form Ab to the piece they lack
Most common Rh phenotype in white and black populations ?
White: R¹r
Black: R⁰r
When is full Rh phenotyping done in blood bank ?
- patient history of Rh antibody
- newborns born to Rh neg females (can make Rh antibody against next Rh pos child)
Which individuals are tested for weak D ?
- blood donors; weak D blood (false Rh neg/ true Rh pos) can be given to recipient (Rh neg) = form Ab to donor blood
- newborns born to Rh neg females (can make Rh antibody against next Rh pos child)
what happens when (partial) weak D blood recipients are given Rh pos ?
they can make Abs to epitope they lack
- SINCE WEAK D PATIENTS TYPE AS Rh NEG = GIVE Rh NEG BLOOD even if they actually have weak D antigens
__ anti-D is used for weak D testing bc of its increased __.
NOVOCLONE anti-D is used for weak D testing bc of its increased SENSITIVITY.
