Unit 4 Flashcards
What abs are good at activating complement
IgM
What abs are capable of causing intravascular hemolysis
ABO
What process causes intravascular hemolysis?
and extravascular?
intra- C3b- activated MAC- C8 and C9 pierce RBCs
Extra- C’ attaches- Fc receptors on spleen and liver destroy the opsonized cells
Acute transfusion reaction are associated with what hemolysis? what type of incompatibility?
What is the most often reason it occurs?
intravascular
ABO incompatibility
clerical error or negligence
What are the main reasons acute hemolytic transfusion rxns occur
-blood too fast
-bacterial contamination
How many ml of blood does it take to cause a reaction
10-15ml
How long should a patient be monitored after transfusion
15-30 min
What are the major complications caused by an acute hemolytic transfusion rxn
DIC, shock, renal failure, death
Explain the cascade effect when intravascular hemolysis occurs
Hb is free in circulation
haptoglobin cleans it
haptoglobin levels go down because it is being used up
if still in blood haptoglobin-> billirubin -> urobilinogen
LDH increases, body is compensating for less O2 distribution by using alternative metabolism
When a transfusion rxn occurs, when would we expect to see a positive DAT and why
if the rxn is immune based
DAT- in vivo sensitization due to abs opsonizing with antigens on RBCs
original test would be neg
after transfusion +
What type of transfusion rxn is this
DAT +
Hemoglobin - decrease
LDH- decrease
bilirubin- increase
haptoglobin- decrease
Acute hemolytic transfusion rxn
immune based
intravascular hemolysis is occuring
What should you do if a patient has a transfusion Rxn
stop transfusion
treat shock
document rxn
check for clerical error- name, unit, match
investigate rxn
What is the best way to prevent a transfusion rxn
patient identification
What type of transfusion rxn is most common in pregnancy
how long does it take to occur after transfusion
FNH febrile non hemolytic rxns
1-2 hrs
Caused by HLA abs in pt plasma against antigens on transfused WBCs and or platelets
FNH
Pt has fever, chills, tachycardia, increased bp 1 hr after transfusion
DAT neg
FNH
rxn is with abs in pt plasma against leukocytes in donor
Best way to prevent FNH
leukoreduction
CMV safe
Pt has erythema, redness, hives, itching 15 min after transfusion
DAT neg
no hemolysis
Allergic rxn
How long for an allergic rxn to occur after transfusion
15-20min
Best way to treat transfusion allergic rxn?
antihistamine
usually can continue transfusion
What type of blood products are most likely to become contaminated by bacteria
platelets
because they are stored in room temp
What are the 3 infection routes for Transfusion associated sepsis
TAS-
phleb
component prep
infection in donor
What 3 organism are capable of causing TAS
pseudomonas, yersinia, serratia
cold gram neg
pt has warm shock (not cold and clammy) high fever, DIC, renal failure, dry skin
DAT neg
hemoglobinuria
Bacterial contamination of blood
If blood looks purpleish and clotted in its bag, cloudy, line of hemolysis
It indicates bacterial contamination
What pts are more likely to get anaphylactic rxns to transfusions
IgA deficient patients who develp an anti IgA through pregnancy or transfusion
can also be caused by drugs like penicillin
blood must be washed
Pt is wheezing, coughing, has no fever, respiratory distress, shock
DAT neg
IgA deficient
anaphylactic rxn
IgA deficient pt must have blood washed before transfusion
If a pt is IgA deficient, what must be done to transfuse plasma? and RBCs
plasma- need rare donor that is also IgA deficient
RBCs- need to wash
Explain what TACO is
hypervolemia due to too much volume of blood or speed of transusion
What pts are more likely to develop TACO
elderly or pts with cardiac/ pulmonary issues
Pt is hypoxic, increased bp, jugular vein is bulging
coughing, headache,
BNP ratio increased
atrial hypertension on Xray
TACO
How to treat TACO
stop transfusion
oxygen,
sit upright
Explain what TRALI is
HLA donor abs attack patient granulocytes in lung tissue
complement activated
causes lung damage
Pt has hypoxemia, fever, chills, pulmonary edema 6hrs into transfusion
HLA abs present in donor and pt
Lung infiltrates on Xray
TRALI
How to treat TRALI
stop transfusion, give oxygen
steriods
How to prevent TRALI
no female plasma. multiparous women have HLA abs in plasma
Which transfusion reaction is associated with donor preformed antibodies or WBCs that attack recipient tissue specifically in the lungs?
TRALI
Why is multiparous women’s FFP discarded and not used for transfusion?
because they can make HLA abs and cause TRALI
Which Ig deficiency should be suspected if a patient has an anaphylactic response to an acellular product? What antibody of the patient is causing the response?
rxn to plasma,
IgA
What is more common, delayed or acute rxns
delayed
acute are usually our fault- almost never happens
When are transfusion rxns seen post transfusion
5-7 days after
What is occurring in a delayed hemolytic transfusion rxn DHTR
ab produced against antigen
What are the causes of a DHTR rxn
immunization
secondary response to RBC antigens
Pt feels fatigue, pallor, flu symptoms 6 days after transfusion
low Hematocrit and hemoglobin
DAT +
increased bilirubin
Delayed hemolytic transfusion rxn
What antigens are likely the culprits of DHTR
Deck
kidd, duffy, C, E abs
How to trat DHTR
give antigen neg red cells that are compatible at AHG
What follow up tests are done if DHTR is suspected?
What are the results if it is occurring
DAT Pos
elution pos- wash RBCs and test for abs present
ABID crossmatch- will be incompatible
What kind of diseases are transmitted by transfusion
hepatitis
CMV
Malaria
HIV
What is the most frequent/ serious complication for transfusion transmitted diseases
Hep B
Hep Cmore long term and serious
How is CMV transmitted and what can we do to prevent it
transmitted by leukocytes
leukoreduced
irradiation for those who need it
What strain of organism causes most malaria cases
how likely is it to be transmitted by blood products
P. falciparum
rare- but more likely in travelers
What causes syphilis, how do we prevent it from being transmitted during blood transfusion
Trepenoma pallodum
RPR, abb testing
if donor has it, 12 month deferment from donating
What causes babesia, how do we prevent it and what does it look like on RBCs
T cruzi
can be fatal, no screening test, maltese cross
Explain what is occuring during graft vs host disease
graft sees host as foreign and mounts an immune response
what causes graft vs host disease
donor lypmhs, or tissue
What type of patients are at most risk of graft vs host
immunocompromised
BM transplant, chemo, infants,
T or F you can get Graft vs host disease from blood from a blood relative
True
tissues and cells are so similar recipient doesnt recognize them as foreign, lymphs proliferate and grow
What is the mortality rate of GVHD and how soon do symptoms start
90% mortality
1-3 days
Pt has rash, fever, diarrhea, failing liver 2 days after received a transfusion from a blood relative
over time they develop sepsis and hemorrhaging
pancytopenia
graft vs host disease
How can graft vs host disease be prevented
irradiation with 25GY
kills proliferating lymphs
What is post transfusion purpura
anti-HPA antibody
HPA is a platelet antigen
destroys donor and patient plts
What type of patients are at most risk of developing post transfusion purpura
women with multiple pregnancies ONLY
pt is excessively bleeding, has large splotchy spots on skin, thrombocytopenia 1 week after transfusion
post transfusion purpura
What is occurring during iron orverload
too much iron creates free radicals that damage liver, heart and endocrine organs
What patients are at risk of getting iron overload
chronic transfusion patients
Pt has multiple organ failure and increased ferritin
irone overload, too many transfusions
What should the transfusionist do after they realize a transfusion rxn of any kind has occured
send post transfusion samples to lab
send back blood unit
send post transfusion urine sample to check for hemoglobin uria
What should the blood bank do after receiving specimen from a transfusion rxn
check clerical work
compare pre to post transfusion specimen
ABORh on post specimen
DAT on post specimen
T/S on post specimen- invalidate old one
What is included in a transfusion rxn workup
ABORh
ab screen
crossmatch
If a patient has a decrease in haptoglobin after a transfusion rxn this mean
intravascular hemolysis
How much irradiation should be delivered to the unit of blood for it to be irradiated ID on the bb card
25 to center
15 to periphery
If doc calls for more blood products for a pt who had a transfusion rxn, but you havent finished transfusion workup what should you do
tell them if they want the blood it would be considered emergency issue
must work up rxn first if possible
How long is a blood bank sample good for
3 days
What antibodies does the immune system create more upon first exposure to something? and second?
1s- IgM
2nd- IgG
Antibody screening must include ___ and ___ to ensure we looked for IgG abs
37C incubation
coombs test
Which is warm? cold?
IgG
IgM
IgG warm
IgM cold
What is clinically significant
IgG
IgM
Why
IgG, decreases RBC survival rate the most
What blood can you give an A pos pt?
First and second choice
Apos or neg then O pos or neg
What blood can you give an A neg pt?
First and second choice
Aneg then O neg
What blood can you give an B pos pt?
First and second choice
B pos or neg then O pos or neg
What blood can you give an B neg pt?
First and second choice
B neg then O pos
What blood can you give an AB pos pt?
First and second choice
AB pos or neg
then A pos or neg
Then B pos or neg
Then O pos or neg
What blood can you give an AB neg pt?
First and second choice
AB pos or neg
then A neg
Then B or O neg
What blood type can you give O pos pt
O pos or O neg
What blood type can you give O neg pt
O neg only
What is in a cross match
What does it prove
When do we need to do extended crossmatched
pt plasma + donor RBCs
ABO compatibility
if known ab is present or if screening cells are positive
What will a compatible crossmatch do
detect error in ABO typing
detect abs in recipient serum
What are 2 things a crossmatch will not do
cant garantee RBC survival
cant prevent immunization
What are the 4 causes for an incompatible crossmatch
ABO grouping of donor or pt is incorrect
-allo ab in patient reacted with ag on donor
-auto ab reacted with ag on donor cells
What does a positive DAT in donor cells mean?
auto ab present
T or F We must crossmatch both RBCs and platelet products
F- we don’t crossmatch FFP
What special considerations should be taken into account with emergency release transfusion
physcian decides, must sign
can give group specific if available
if not then give O- to F childbearing age and children
O+ to all others
remember this blood has not been crossmatched
What must you always do with donor emergency blood before giving it to the doc
retain a segment
Must still crossmatch
T/S
if incompatible- must tell Doc and BB physician
What is an MTP
what is included in it
massive transfusion protocol
total volume exchange 5 units of blood or more
FFP, cyro and platelets
What does a T/S look like after a pt has an MTP
abnormal- mixed field for weeks
How long should you maintain the blood after an MTP
7 days of pt and donor samples
T or F the original pt sample is still good after an MTP
false- it is invalid and must be discarded
What is given in an MTP
4 to 6 type specific or cross matched RBCs
4 plasma
1 platelet
What are autologous units and what special considerations should be used for them
should do crossmatch
pt donates their own blood in prep for a surgery
What considerations for neonate transfusions
forward type testing only
neonates do not produce their own abs
Where are neonate abs from if they are present
from mom
How are RBC transfusions for neonates given
what are the requirements
in a syringe
must be less than 7 days old
O neg or compatible with both mom and baby
CMV neg and leukoreduced and irradiated
Hb S neg
How much blood is given in neonate transfusions
10mL over 2 to 3 hrs
What requirements for returning blood to BB
undisturbed container
temp within 10C
blood inspected
one sealed donor segment on container
no more than 30 min outside of BB at room temp
8hrs if in cooler
What is MSBOS
maximal surgical blood order schedule
blood products for surgical procedure
When are electronic crossmatches permitted
if pt has had at least 3 ab screens
no abs present ever
What are autoantibodies
abs that react with antigens on the same persons red cells
What antigen groups are cold
LIPMAN
What is the purpose of ab screens
to find clinically significant antibodies
IgG or warm abs
What are the reagent cells used in ab screen
O cells
in sets of 2 or 3 with unique antigram
antigen typed for major antigens
What are the 3 phases of an IAT
What ingredients
pt plasma + reagent cells
Immediate spin Ab test
read at 3 stages
IS-IgM- room temp cold ab
37C- IgG warm abs
AHG ad CC- IgG
when do we need to do an antibody panel
If screen cells are pos
CC are pos
confirms there is an ab present and it needs to be IDed
When are IAT ab screens necessary
pts with a history of abs or currently demonstrating abs
What are enhancement medias for
for 37C and AHG testing to increase ab binding if abs are present
What to do if ab screening leads to ab ID panel
critical result, must call
What are the reagents in an ab panel
10-20 vials of known antigens
If the auto control is pos on ab panels what does that mean? if it is neg?
+ auto ab present
- allo ab present
What are the ingredients in auto control of ab panel
patient cell + patient serum
What investigative questions should be asked if an ABID is pos
ask if pt has ever been pregnant
if any transfusions
if any transfusion rxns
search for old BB records
document all findings and who you spoke to
What antibodies are destroyed by enzymes
duffy, MNs
What antibodies are destroyed by enzymes
duffy, MNS
What are the 4 enzymes used for enzyme treated cells
ficin
papain
trypsin
bromelin
What abs are enhanced by enzymes
Rh, Lewis, P, Kidd and I (i)
Klipr
What extra steps when using enzyme enhancement
increased incubation time
What antigens can’t be used on ABID panel cells that use enzyme treated cells
MNS and Duffy
What ab is not affected by enzymes
Kell
What is enhancement media for? Name them
help increase agglutination
LISS, bovine albumin and PEG
has increased serum to cell ratio
has altered pH
What does LISS do
what does it stand for
Low ionic strength saline
increases ab uptake
What does PEG do
concentrates ab in test environment in LISS
What do papain and ficin do
Whyremove neg charges from RBCs to reduce zeta potential, denatures some of their antigens
Why does enhancement media have an increased ratio
larger serum to cell ratio
to help attach antigens to RBCs
can help in pts with less reactive abs like the elderly
What is neutralization for
to neutralize abs that are in the way of us finding another
helpful for multiple abs
What nuisance abs do we want to get rid of
Lewis, P1, Xga
What are adsorptions
method to remove unwanted abs from serum or plasma
mix RBCs with antigens for nuisance ab so they can attach
when spun they will be in pRBCs and not plasma
for cold or warm autoabs
Explain what allo-adsorptions and auto-adsorptions are
allo-cells with a known phenotype other than patient cells
auto- let pt plasma bind the same pt RBCs
What is the risk of doing adsorptions if the pt had a transfusion in the last 3 months
might take up allo-abs and auto abs, donor cells will cause stronger rxn than allo abs
When do we need to combine elutions with alloadsorptions
when a patient has an anti-G
How can we get a better removal of Abs in warm auto absorption
pretreating with enzymes
What is an elution
the removal of abs or complement that are bound to RBCs
abs can be recovered, IDed and tested
When are elutions used
on pos DAT or autocontrol with a recent transfusion history
Explain how to do an elution
Wash RBCs usually x3
last wash must be saved for QC
last wash must be neg
What are elutions helpful for
suspected HDFN and Auto Immmune Hemolytic anemia or transfusion rxn
What kind of Abs are detected at IS
IgM
What type of Abs are detected at 37C
IgG
Adsorption remove abs from ___
Elution removes abs from ___
adsorption- serum/ plasma
elution- RBCs
What is the most common type of elution
acid elution with digitonin
destroys RBCs, allows us to collect IgG from supernatant
How does Lui Freeze elution work
freezes cells to hemolyze them
RBCs lyse during thaw
T or F panel cells are all the same on different lots
F- they are always different
What might affect the positivity of an ab panel
dosage
Kidds Rh Diffy MNS
What do homozygous pairs look like an a panel? and hetero?
homo- 0, +
heter- ++
What part of the panel should you use to rule out and why
negative, because there was no reactivity there, ab is present by its not with that specific donor, can get ruled out
What antigens can you rule out
homozygous pairs
max strength and expression
What are the exceptions to homozygous rule outs
Kell- very low frequency, hard to find homozygous pairs, instead can get ruled out with 2 or 3 hetero or 1 homo
C and E- with suspected anti-D
2,3 hetero to rule out when pt has anti-D
What is the RH SOP for rule outs
need 2 neg cells, at least 1 must be homozygous
Explain the rule of 3
once ab specificity is determined
must validate statistical significance with a 95% confidence interval
must have 3 pos and 3 neg rxns for the ab you found to prove its there and report it out
Where can you show rxns for rule of 3
on screening cells+
on panel+
on repeated panels+
use select cells if rule still not met
What check cells you need to choose
cells that are neg for the antibody in question AND homozygous pos for the antigen you want to rule out
What to do if autocontrol is pos
Run a DAT, if pos and pt was recently transfused, must do elution
What to do once ab specificity is confirmed
antigen typing, find units of blood that are neg for antigens that are clinically significant
extended crossmatch with donor
How can we know how long it will take to find the specific antigen negative unit we need for a pt with a clinically significant ab
units = (# of units needed)/ ( negative antigen frequency)
by calculating the antigen negative frequency
# units = (# units needed) / (negative antigen frequency)
Docs need 2 units of pRBCs on patient that has an anti E
E present in- 30%
2/ 70 = every 3 units of blood do not have anti E
Doc needs 1 unit of blood that is anti-K and anti-e
K present in 9%
e present in 98%
91% K neg
2% e neg
1/ (0.91x0.02) = every 55 units of blood will be compatible
An A neg person with Fya needs blood, what is the probablity we will get that blood
Fya present in 65%
know the ABO frequencies yourself
Pt can get A neg or O neg blood
A-35% neg 15%
O 45% neg 15%
1/ (0.8x0.15x0.35) = 24
