Exam 3 Flashcards by Lizzy C

This method is used to
screen for unexpected
antibodies in the clincial lab
prior to transfuion.

Antibody Screen

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In addition to meeting the
rule of 3, you must also
perform this test on the
patient’s own RBCs to
confirm the antibody
specificity

Phenotyping the patients
RBCs for the corresponding
antigen

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After identifying an
antibody, you determine it
does NOT meet the ‘rule of
3’, what does this mean?

95% confidence that the correct antibody has NOT been identified

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Describe what makes an
antibody clinically
significant.

Allo-antibody that causes decreased survival of RBCs with target
antigen
Usually IgG, reacting at 37C or AHG

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List 3 different things you
might see in an antibody
panel to indicate multiple
antibodies in a patient’s
serum

Pattern not fitting
single antibody
Variation in the
phase of reaction
Variation in the
strength of antibody

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This type of unit cannot
crossover into the general
blood bank if not used, and
is often associated with a
higher cost.

An autologous donation

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After pregnancy, a donor is
deferred from donating for
this time period

6 weeks post pregnancy

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List the parts of the ‘pre-
donation screening.

Pre-donation Screening
Includes:
-Registration
-Medical/Donor History
Questionnaire (DHQ)
-Physical Exam

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This is the deferral period
for a person that donates a
‘double red’ or ‘power red’
via apheresis

16 weeks

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This is the different between
the processing of whole
blood in the US vs Canada

Canada & Uk > Buffy coat method > 1 hard spin & pool
US > PRP (platelet rich plasma method > light spin, hard spin

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This list of questions is
given to screen prospective
blood donors to for
infectious risks, and the
order CANNOT be changed
by collection facilites.

Donor History Questionnaire

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Following treatment and
recovery from malaria, a
person is deferred from
donating blood for this time
period

3 years

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This has been largly
responsible for the most
recent decrease of the
‘window period

Nucleic Acid Testing (NAT)

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List the required hbg & hct
values for a male & a female
to donate a unit of whole
blood

Female: 12.5 g/dL & 38%
Male: 13.0 g/dL & 39%

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The procedure that is
performed when a previous
donor of a blood product,
tests positive for an
infectious disease marker,
not present in previous
donation

Donor Lookback

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These two crossmatching
procedures will only be able
to detect ABO
incompatibilites.

Immediate Spin (IS) & Computer
Crossmatch

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After transfusion, the donor
sample & pre-transfusion
recipent sample must be
kept for this long

7 days

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A ‘type & screen’ includes
these types of tests

ABO & Rh, Antibody Screen & ID if +

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A patient has an anti-K that
was identified back in 1965.
If she is getting a unit of
pRBCs the blood bank can
perform this kind of XM

AHG Crossmatch only!!!

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Define ‘massive transfusion’

8-10 RBC units in <24 hours
4-5 RBC units, in less than 1 hour

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Patients who are IgA
deficient should be
transfused with this special
kind of RBCs

Washed RBCs!

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A unit of RBCs collected 1
week ago and irradiated
today has this shelf life.

28 days (or the expiration date of unit- whichever is sooner)

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Thawed cryoprecipitate has
a shelf life of

6 hours!  at what temperature??
Room Temperature!!

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This product is the most
appropriate for a patient
with a multiple coagulation
factor deficiency

Study These Flashcards

Fresh frozen plasma

As RBCs age in storage, this molecule decreases, which causes hgb’s affinity for oxygen to increase

2, 3 DPG Left Shift

This process is performed on pRBC units to prevent immunocompetent donor T- lymphocytes from engrafting in an immunocompromised recipient

Irradiation

This is the most likely reason frozen, deglycerolized RBCs would be transfused

A patient with antibodies to a high-frequency antigen

This is the expected outcome after the transfusion of 1 unit of packed RBCs.

Increase the hemoglobin by 1 g/dL and the hematocrit by 3%

Give one example why you would use an absorption

To remove an AUTO-antibody from a patient’s plasma (process of removing antibodies from serum, by incubating with corresponding antigen)

Describe the reason why specimens on patients recently transfused/pregnant should be used < 3 days after collection.

Recent pregnancy or transfusion may stimulate antibodies that are not detectable at the time of collection

An antibody screen & panel have revealed the presence of an allo-antibody in the patient’s plasma. What would be the next step to find compatible units for the patient

Antigen type patient’s cells & donors unit to be crossmatched for the corresponding antigen

Incompatibilities can be seen with the Immediate Spin (IS) crossmatch for all the following reasons EXCEPT

Correct ABO unit selected for the patient

Samples of the blood donor and recipient, used in crossmatching must be stored in the blood bank for a minimum of how many days after transfusion

7 days

What is an antibody screen?

2-3 reagent cells with known antigens on them. If there is agglutination in any of the stages then move to the panel.

Rule of three

Confirms antibody presence with a 95% confidence. If not enough cells to satisfy the rule then extend the panel and use a few more cells.

Selected Cells

When you pick cells specifically to test for one antibody (confirmation)

Neutralization

Commercial substances that bind antibodies to create no reaction when tested with reagent cells.

Proteolytic enzymes

Can be used to enhance and destroy antigens

Sulfhydryl reagents

differentiate between IgG and IgM. Breaks disulfide bond in IgM. DDT

ZZAP

Enzymes and DDT

Cold Autoantibody

Reacts at RT with most panel cells, and positive autocontrol.

Warm Autoantibody

more common, +DAT. Rh is main target, can cause hemolytic anemia

Adsorption is

the process of removing auto Ab by incubating plasma with corresponding antigen (patient cells)

T/F autoantibodies can hide clinically significant alloantibodies

True

Immediate spin crossmatch

preformed if there is no detection or history of clinically significant antibodies

Antiglobulin crossmatch

preformed when there is a clinically significant Ab has been ID or theres a history

Steps to donor selection

Registration, medical history, physical exam, informed consent, collection of blood, post-donation testing and component separation

How often can you collect blood?

8 weeks

US separation

Platelet rich plasma

Canada+Europe separation

Buffy Coat Method

Apheresis

Blood donation that separates one component of the blood to be collected while giving back the other components

Plateletpheresis frequency

every 7 days up to 24x a year

Plasmapheresis frequency

serial donors=2x a week regular=every 4 weeks

Double Reds

deferred for 16 weeks female has to be taller than 5'5" and over 150lb Male has to be taller than 5'1" and over 130lb

Donor lookback protocol

When a donor tests positive for a viral marker -notify donor -notify blood product recipients -find additional components -quarantine previous units, additional testing, desstory previous units if pos

RBC storage times

42 day fridge 10yr freeze

Plasma storage

1 yr freeze 7yr deep freeze freeze within 8 hrs of collection

Cryo

prepared from FFP. Storage at -18 for 1 year, must be used within 6 hr of thaw

What is it important to do if someone has an IgA deficiency?

Wash the RBC

Exam 3 Flashcards

(59 cards)