practice questions Flashcards
warm reactive
IgG
detectible at immediate spin
IgM
small enough to cross the placenta potentially causing HDFN
IgG
best at fixing compliment
IgM
first seen in the primary immune response
IgM
Which protein in the compliment system is identifiable on the red cell surface after compliment has been activated?
C3b
An antigen is expressed on the outside surface of the red cell. What does that mean for the patient gene
the patients gene codes for the allele of the specific antigen
True or False: Additive solutions increase the shelf life of red cell products by requiring the removal of plasma from the red cells.
false
- not all additive solutions require the removal of plasma
Which grade would you give to an agglutinate that has a single large chunk an several smaller chunks in the tube?
3+
Which blood group was named for the scientists who were researching an antibody that caused hemolytic disease of the newborn?
LW
- Landsteiner weiner were researching it and discorvered LW on accident but named it D, other scientists came and discovered the mistake and named the initial discovered antigen LW
- part of the RhAG complex for stabilization (decreases expression with age)
Which antigen in the Rh system has a significantly different (>20% different) antigen frequency in the Black US population vs the White US population?
big C
- black is more likely to have little c (98%) than big c (20%), white is 68% big C though little c is still more common at (80%)
Which genotype would a person have if they inherited RhD and Rhce genes from their mother and RhD and RhCe from their father?
R1R0
partial D antigen has a mutation on the ____ of the cell
outside
weak D antigen has a mutation on the protein on _____ of the cell
inside
A frameshift mutation in the RhD will result in a patient who is:
Rh negative
- will still have C/c and E/e but D will not be translated
True or False: a 4 month old baby who is Rh negative is expected to have anti-D in their plasma.
false
- anti-D is formed after immunizing event
what serological result is seen when you forgot to add plasma to IAT
negatives in AHG
what serological result is seen when you over wash in IAT
no button in AHG
what serological result is seen when you under wash in IAT
negative in CC phase
which class of Ab reacts best at room temp
IgM
IgG Ab are clinically significant for HDN because
they can cross the placenta
hemolysis is a positive reaction that indicates you have most likely identified antibodies that
- react at AHG
- fix compliment
- cross the placenta
- are immune stimulated
fix compliment
- compliment ends in hemolysis
which of the following is known as the membrane attack complex in the classical pathway
C5b,6,7,8,9
as RBCs are stored which of the following increases
- plasma potassium
- 2,3-DPG
- ATP
- pH
- plasma potassium
- along with lactic acid and hgb as they are released from the cell and metabolism
what is the longest length of time that the FDA says red cells can be stored for
42
- additive solutions reduce hematocrits allowing less viscosity and easier infusion of packed RBCs while harvesting max plasma
when there is a shift to the left hgb affinity for oxygen does what
increases
- holds oxygen tighter and does not release into tissues
- 2,3 DPG will decrease as O2 takes its place on the hgb
what is the maximum time a sample may be obtained before a transfusion for pretransfusion testing
3 days
what does AB gene on chrom 9 code for
transferase to add either N-acetyl galactosamin (A) or galactose (B)
what does H gene code for
chrom 19 codes for fucose to be added to precursor substance to form H antigen
what does Se code fo
chrom 19 codes for fucose addition to precursor substance type 1 to make H substance
what is the most common cuase of anti A 3+mf and anti B 4+
transfusion
- two populations of cells
aquired B antigen is found in which individuals
group A persons
- part of N-acetylgalactosamine is cut off to resemble B antigen in infections
what subgroup is suspected with anti-B gives 1+mf and anti-AB 1+mf and A1 cell 3+
B3
- 3 subgroup = mixed field
- reverse type for subgroups will still show normal reactivity
you would use Ulex europeaeus reagent to investigate what
potential bombay
- specific for H antigen
which blood group has the most amount of H substance
O
- O>A2>B>A2B>A1>A1B
if the patient with following results was a secretor, what substance would that person have in their secretions:
Anti A: 0
anti B: 4+
A1 cell: 4+
B cell: 0
- B, Leb
- secretor means terminal fucose is added, if patient has FUT 3 then they will make lewis B
the lewis gene codes for a transferase that transfers a sugar onto precursor substance, what is that sugar
fucose
- places it in subterminal position
a patient has HH, LeLe, sese, A genes. what antigens will be expressed on their red cells
A, H, Lea
- Lea since non secretor status means no terminal fucose is added to secretions and no Leb can be formed
which antibody reacts with Rhesus baby cells but not rhesus adult cells
anti - LW
- expressed in higher amounts in babies and decreases with age
a patient has developed multiple Abs to the Rh system. Anti-D, anti-C, anti-E/ how many units are tested to find compatible blood
1 Rh negative unit
- Rh negative is most likely to be dce so any Rh neg labelled bag should also be C and E neg (making it dce)
which genotype may demonstrate dosage with anti-C
R0r’
- C in trans to D has an inhibitory effect
- acts as antithetical pari
- capellini effect
which offspring is not possible from a mother who is R1R2 and a father who is R1r
R2/R2 (DcE/DcE)
an individual has the following Rh phenotype: D+, C-, E+, c+, e-
what is their most likely genotype if they are Asian
R2R2 (DcE/DcE)
how are weaker than average reactions with anti-D categorized for DONOR cells
Rh pos
- a pos reaction is still pos and cannot give Rh pos to Rh neg
which op is the weak D test performed in
baby
- needs to protect mother from immunizing event
which patient would you expect to make anti-D
- pregnant pt w/ D mosaic
- pt who gives weakly reactive D
- pt who has made anti-c
- pt who is immune comp and transfused Rh pos blood
pregnant with D mosaic (partial D) -=> forms antigens against full D
how is testing for Rh antigens and Ab diff from ABO testing
- ABO ANTIBODIES can be tested at room temp
- Rh ANTIBODIES need AHG
which genotype shows the strongest reaction with anti-D
D–/D– (exhalted D)
- D masks CE during transcription and is translated instead and many more times
which enhancment colloid works by removal of water to concentrate antibody
polyethylene glycol (PEG)
which of the coombs tests does not require check cell addition to verify washing
gel
- no check cells or wash
