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S3B4 Pathology > Blood Bank I > Flashcards

Blood Bank I Flashcards

1
Q

Transfusion Medicine is a term that encompasses what types of medical components?

A
  • blood donation
  • component preparation
  • serology & infectious disease testing
  • transfusion therapy
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2
Q

List the general steps that are part of routine pretransfusion testing.

A
  1. Identification on blood & paperwork match
  2. ABO & Rh(D) typing of recipient & screening of the serum
  3. If the screen in positive, perform an antibody identification test
  4. Crossmatch donor blood cells with recipients’s serum (final check)
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3
Q

What type of antigens are ABO?

A

carbohydrate

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4
Q

Genes for blood type dictate whether an A and or B antigen should be added to what precursor?

A

H antigen

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5
Q

How do people develop ABO antibodies?

A

naturally occurring IgM antibodies that do not require previous exposure

usually present by 6 months of age

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6
Q

What aspect of the ABO antibodies make it potentially dangerous to combine blood types?

A

IgM antibodies fix complement & may cause intravascular hemolysis

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7
Q

How is it possible for a mother to give birth to a child with a different blood type?

A

IgM antibodies do not cross the placenta, so they do not cause hemolytic disease of the fetus & newborn

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8
Q

What are the main antigens of the Rh system?

A

D (Rh +), C, c, E, e

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9
Q

What type of antibodies are developed in response to Rh antigens? What is the significance of this?

A

IgG

may cause delayed hemolytic transfusion reactions

hemolytic disease of the fetus and newborn (b/c can cross the placenta)

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10
Q

IgG antibodies cause what type of hemolysis?

What about IgM?

A

IgG : extravascular hemolysis (not efficient at fixing complement)

IgM : intravascular hemolysis (better at fixing compliment)

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11
Q

What is hemolytic disease of the fetus & newborn? (HDFN)

A

have Rh (-) mother

If first baby is Rh (+) - baby is protected because mother has not been exposed to Rh antigen & therefore has not made antibodies against it

At parturition, there will be intermingling of mother & baby RBC, and mom will start forming antibodies

If mom get pregnant again with a RH(+) baby, her pre-formed IgG antibodies can cross the placenta & cause serious damage to the fetus

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12
Q

What is the most severe manifestation fo HDFN?

A

Hydrops Fetalis

accumulatio

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13
Q

What is Hydrops Fetalis

Causes?

A

accumulation of clear, watery fluid in the tissue or cavities of the body of the fetus

Causes

  • immune mechanisms:
    • blood group incompatibilities
  • non-immune mechanisms:
    • some infections,
    • fetal cardiac disease,
    • other structural abnormalities
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14
Q

Describe the pathophysiology behind immune causes of Hydrops Fetalis

A

IgG antibodies cross the placenta & coat the fetal RBC

those fetal RBC are then picked up and destroyed in the fetal liver/spleen

liver & spleen can become enlarged

can go into liver failure & it stops making enough proteins, developing massive ascites

fetuses can also have nucleated (immature) RBC in the peripheral blood

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15
Q

Is hemolytic disease of the fetus & newborn more likely to be caused by Rh incompatibility or ABO incompatability?

A

ABO – if mother has ever been exposed to one of these antigens, she will also develop IgG antibodies against them, which are able to cross the placenta

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16
Q

What co-morbid conditions are commonly seen in infants born with HDFN?

A

Jaundice

Kernicterus

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17
Q

What pathology is shown in the provided image? It is most common in what demographic?

A

Kernicterus

blood-brain barrier is suboptimal due to prematurity or acidosis

18
Q

What is Kernicterus & what is the clinical presentation?

A

High levels of unconjugated bilirubin that crosses the blood brain barrier & deposits in the brain

  • Cerebral edema
  • Bright yellow staining of the brain (b/c unconj. bilirubin)
19
Q

When is Rh Immunoglobulin administered to patients?

A
  • Given to D-negative pregnant women
    • at 28 weeks gestation
    • post partum within 72 hours
20
Q

How does Rh Immunoglobulin work when it is administered to pregnant patients? In what situation is it contraindicated?

A

anti-D coats the fetal RBC

the coated RBC are removed from the blood by the reticuloendothelial system

this prevents D-negative mothers from making anti-D antibodies

no contraindications, but it is of no value if anti-D antibodies have already formed

21
Q

What is the difference between Forward Typing & Reverse Typing?

A
  • Forward Typing
    • Patients cells are combined with reagent sera
    • info about which ABO antigens are present in patient’s cells
  • Reverse Typing
    • Patients serum is combined with reagent cells
    • info about which ABO antibodies are present in the patient’s serum

Should have OPPOSITE reactions

22
Q

Identify which test tube indicates a positive test, negative test & a moderately positive test for agglutination

A
23
Q

The provided reactions indicate what blood type?

A

A positive

24
Q

How would you grade the following test tubes?

A

+4 = positive for agglutination

0 = negative for agglutination

25
Q

What is a DAT and in what situations is it performed?

A

Direct Antiglobulin Test - detects in vivo attachment of immunoglobulin or complement to red cells

  • Used in:
    • autoimmune helolytic anemia
    • transfusion reaction
    • HDFN
26
Q

What is an Indirect Antiglobulin Test & in what situations is it used?

A

Detects in vitro attachment of immunoglobulin or complement to red cells

  • Used for:
    • antibody screening & crossmatching
    • antibody identification panels after positive antibody screen
27
Q

Why do you perform an antibody screen?

A
  • detect unexpected antibodies in patient’s serum - people who receive regular transfusion are susceptible to developing new antibodies
28
Q

What are the 2 spins performed in an antibody screen & why are each of them performed?

A
  • room temp immediate spin testing detects IgM antibodies
  • Testing at 37 degrees C & AHG phases detects significant IgG antibodies
29
Q

What type of cells are used for antibody screening?

A

type O with known surface antigens, purchased from a manufacturer

30
Q

What are the clinically significant antibodies?

A
  • Usually IgG
  • React at 37 degrees C
  • Kell (K, k)
  • Kidd (Jka, JKb)
  • Rh (D, E, e, C, c)
31
Q

What is the “last check” for blood typing before the transfusion is performed?

A

Crossmatch

confirms ABO typing - sometimes picks up antibodies not detected in antibody screen

32
Q

When is the crossmatch carried through to 37 degrees with AHG?

A

if the antibody screen is positive

the immediate spin is done at room temp & if screen is good, then this is usually enough

33
Q

What are the 3 emergent crossmatch options?

Include how long it takes to receive each transfusion & specifics of administration for each type.

A
  1. Uncrossmatched Blood - O-positive or O-negative
    • available in 5 min
    • ONLY O-neg to young females & females of childbearing age
    • O-positive is okay for males & postmenopausal females
  2. Emergency Type-Specific
    1. available in 10 min
    2. ABO & Rh typing done, but no antibody screen yet
  3. Type Specific with full crossmatch
    • available in 30 min, if no unexpected antibodies
    • ABO, Rh, antibody screen & crossmatch are done
34
Q

What are the two type of pre-operative blood orders?

A
  • Type & Screen Only
    • ABO, Rh, & antibody screen but no crossmatch
    • ordered when blood use during surgery is not expected
  • Type & Crossmatch
    • ABO, Rh, antibody screen & crossmatch have been performed – ready for transfusion
    • order when blood is expected to be used during surgery / when unexpected antibodies on screen
35
Q

Answer the following questions with reference to packed red blood cells:

Does it require a crossmatch?

Standard volume?

How long can it be stored & in what conditions?

How quickly must it be used once it leaves the Blood Bank?

A

Requires crossmatch

~300mL

May be stored for up to 42 days at 1-6 degrees C; may be leukodepleted

must be transfused within 4 hrs of leaving Blood Bank

35
Q

Answer the following questions with reference to packed red blood cells:

Does it require a crossmatch?

Standard volume?

How long can it be stored & in what conditions?

How quickly must it be used once it leaves the Blood Bank?

A

Requires crossmatch

~300mL

May be stored for up to 42 days at 1-6 degrees C; may be leukodepleted

must be transfused within 4 hrs of leaving Blood Bank

36
Q

By how much should 1 unit of packed red blood cells change the hemoglobin / hematocrit?

A

raise hemoglobin by 1 g/dL or hematocrit by 3%

37
Q

What is the concern with massive transfusions & what risks is it associated with?

A

>10 units

may dilute coagulation factor levels & platelets → bleeding

risk: hepatitis, allo-immunization, other rxns

38
Q

What is the purpose of leukocyte depleted RBCs?

A

Special Type of RBC Transfusion

decreases risk of febrile non-hemolytic transfusion reaction

39
Q

What is the purpose of frozen deglycerolized RBCs?

A

Special types of RBC transfusion

for rare blood types & military use

can be stored frozed up to 10 yrs - expires w/in 24 hrs of thawing and deglycerolization

40
Q

What is the purpose of washed RBCs?

A

Special type of RBC transfusion

washed 3x to remove platelet, plasma & 90-99% WBC - expires 24 hrs after washing

for IgA deficient patients & others with severe reactions to plasma proteins

41
Q

CMV-negative blood products are reserved for what groups of people?

A
  • Patients with the highest risk of contracting CMV infections
    • intrauterine transfusions, neonates, infants <4 months
    • allogeneic bone marrow transplant recipients
    • liver transplant recipient <18
    • recipient of lung, heart, heart/lung transplants
    • cardiovascular surgery patients under 12 months
    • immunocompromised patients (on request)

S3B4 Pathology (6 decks)

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