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Block 7 Week 3 > Fung: Transfusion Medicine > Flashcards

Fung: Transfusion Medicine Flashcards

1
Q

At a blood bank, tubes of blood are first spun to look for (blank). Next, they are tested via the IAT phase to detect RBCs coated with (blank). Which step in this process is more often significant?

A

In tube testing, the blood will first undergo immediate spin to look for IgM antibodies - these are usu insignificant; next is the IAT phase in which RBCs are coated with IgG +/- complement and antibodies that react and cause agglutination are more often significant

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2
Q

What is the difference between a direct antiglobulin test and an indirect antiglobulin test?

A

DAT: in vivo - look for RBCs already bound by antibody

IAT: in vitro - look for antibodies present in the patient’s serum

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3
Q

an inherited character of the red cell surface detected by a specific alloantibody

A

blood groups

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4
Q

How many blood groups are there currently?

A

339

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5
Q

List some red cell antigens that we use clinically

A 
ABO
Rh (D)
Secretor
Lewis (A or B)
Kell (K or k)
Duffy (FyA or FyB)
Kidd (JkA or JkB)
I (I or i)
MNS
P
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6
Q

When are blood groups clinically significant?

A

when they can cause hemolytic transfusion reactions or hemolytic disease of the newborn/fetus

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7
Q

Most significant RBC antibodies are (blank), (blank), and require (blank)

A

IgG (can cross the placenta)
warm reactive
previous exposure

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8
Q

Most insignificant RBC antibodies are (blank), (blank), and (blank) occurring

A

IgM; cold reactive; naturally

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9
Q

The H antigen on RBCs is further modified to make (blank) and (blank) antigen. (blank) antigen has no further modification of H antigen.

A

A; B; O

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10
Q

T/F: Your ABO genotype is determined by 3 co-dominant alleles on the long arm of chromosome 8

A

false; chromosome 9

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11
Q

On what other cells/tissues besides RBCs are ABO antigens found?

A 
platelets
endothelium
kidney
heart
lung
bowel
pancreas
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12
Q

When are ABO antigens present on fetal RBCs?

A

by 6 weeks of gestation; reach adult levels by age 4

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13
Q

Most common blood type in Caucasians, AA, Asians, and Native Americans?

A

OO

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14
Q

What is the Bombay blood type?

A

Lack of H, A, and B antigens due to lack of H and Se genes

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15
Q

How do you get antibodies to opposing blood types? At what age do these appear?

A

they are naturally occurring; appear at 4 months of age, reach adult levels at 10

ex: Anti-A, Anti-B, Anti-A,B

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16
Q

Which blood type is at the highest risk for hemolytic disease of the fetus/newborn?

A

Type O

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17
Q

When you test a patient’s serum, you use forward typing and reverse typing. How do these differ?

A

forward typing: determines antigens present on patient’s or donor’s cells (ex: If type A, will test + for Anti-A antigen)

reverse typing: determines antibodies in patient’s or donor’s serum or plasma (ex: if type A, will test + for B cells)

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18
Q

Red cell grouping

Patient’s red cells agglutinated by test anti-A, anti-B antibodies

A

Forward typing

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19
Q

Serum grouping

Patient’s serum or plasma agglutinated by test A1 and B RBC

A

Reverse typing

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20
Q

There are two Rh genes. What are they? Which is very immunogenic?

A

RH (D) and RH (C/c, E/e);

D makes the most antibodies and is very immunogenic

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21
Q

Will HDFN occur during a mother’s first pregnancy?

A

no, unless the Rh- mother was previously transfused and exposed to Rh+ blood

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22
Q

How can you prevent HDFN if you know a mother is Rh- and her fetus is Rh+?

A

Give RhIG (preparation of anti-D antibody) to the mother at 28 weeks gestation and <72 hrs after birth

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23
Q

When should you NOT administer RhIG to a mother?

A

if the Rh- mother already has anti-D antibodies
Rh+ mothers
Rh- mom with Rh- baby

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24
Q

How much RhIG should you administer?

A

300micrograms (1 vial) per 30mL of D+ whole blood

or

300micrograms per 15mL of D+ RBCs

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25
Q

What are 3 tests that can be used to determine HOW MUCH RhIG should be administered?

A

fetal blood screen: qualitative
Kleihauer-Betke: quantitative (tells you what percentage of mother’s blood contains fetal blood)
Flow cytometry: also quantitative, looks for D antigen

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26
Q

What is the KB%? What should this value be multiplied by in order to determine how much D+ baby blood is in the mother? What should this value be divided by in order to determine how much RhIG to give the mother?

A

percentage of fetal cells that are seen in maternal blood; multiply by mom’s blood volume to find out how much RhIG to give; divide by 30 - this will give you a value for RhIG

  • *if there is a decimal less than 0.5, round up once
  • *if greater than 0.5, round up twice
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27
Q

Similar biochemistry to ABO system
In secretors, Leb mostly formed
In non-secretors, mostly Lea formed
Insignificant, naturally occurring, cold-reacting IgM antibodies

A

Lewis system

28
Q

Anti-M and anti-N: Insignificant, naturally occurring, cold-reacting IgM
Anti-S, anti-s, anti-U: Significant, exposure requiring, warm-reacting IgG
Anti-M is rarely associated with severe HDFN

A

MNS system

29
Q 
Antigens are built on 2 types of chains
Simple (i) chains found in neonates
Branched I chains found in adults
Insignificant, naturally occurring, cold-reacting IgM auto-antibody
Auto-anti-I: 
Cold agglutinin disease 
Mycoplasma pneumonia infections
Auto-anti-i:
Infectious mononucleosis
A

I system

30
Q

What 3 disease states can be associated w Auto-anti-I and Auto-anti-i?

A

anti-I: cold agglutinin disease, Mycoplasma pneumonia infections

anti-i: infectious mononucleosis

31
Q

Similar biochemistry to ABO system
P antigen is the parvovirus B19 receptor
Pk antigen is receptor for various bacteria and toxins
Insignificant, naturally occurring, cold-reacting IgM
Auto-anti-P:
Paroxysmal cold hemoglobinuria
Biphasic IgG autoantibody (bind cold, hemolyzes warm)

A

P system

32
Q

The P antigen is the (blank) receptor

A

parvovirus B19

33
Q

Significant, exposure requiring, warm-reacting IgG (with IgM component)
Can fix complement with IgM component
Severe acute HTR possible
Delayed HTR, anamnestic, intravascular and severe
Mild HDFN

A

Kidd system

34
Q

What is significant about the Kidd antibody?

A

if you have anti-Kidd antibody, it will decrease over time; however, as soon as you are re-exposed to the antigen, you will mount a severe response

**Kidd kills bc of hemolysis w/i blood vessels

35
Q

K antigen low frequency; k antigen high frequency (99.8%)
Anti-K
Most common non-ABO antibody after anti-D
Significant, exposure requiring, warm-reacting IgG1
Most due to transfusion, not pregnancy
Anti-k
Very uncommon due to high frequency antigen
Severe acute or delayed, extravascular HTR
Severe HDFN
McLeod phenotype/ McLeod Syndrome
All Kell antigens decreased
Hemolytic anemias with acanthocytes, myopathy, ataxia, peripheral neuropathy, cardiomyopathy
X-linked chronic granulomatous disease

A

Kell

36
Q

Which kell antigen do most people (99.8%) have? So, what antibody do most people have?

A 
k antigen (vs rare K antigen);
anti-K antibody is the most common non-ABO antibody after anti-D
37
Q

Anti-Fya more common and significant than anti-Fyb
Significant, exposure requiring, warm-reacting IgG
Severe HTR, delayed and extravascular
Mild, but occasionally severe HDFN
Fy(a-b-) most common phenotype in African-Americans
Fy(a-b-) are resistant to Plasmodium vivax and P. knowlesi infection

A

Duffy

38
Q

Which duffy antibody is more common?

A

Anti-FyA

39
Q

T/F: For blood donation, donors are screened by history (name, address, DOB, last donation, medications, risk factors, etc) and physical criteria (general appearance, arm check, weight, pulse, BP).

A

True

40
Q

What are these?

High risk behavior for AIDS (IVDA, male-male sex, exposure)
Receiving money for sex
Serologic positivity for HIV, HBV, HCV, HTLV
Viral hepatitis after 11th birthday
Use of transfusion clotting concentrates
History of babesiosis or Chagas disease
Growth hormone from human source
Insulin from bovine sources
Dura mater graft
Lymphoma or leukemia
Medication teratogens: Tegison
vCJD risk
A

reasons for permanent deferral for blood donation

41
Q

What are these?

Recovered from malaria
Immigrants from malaria endemic areas (5 years of living)
Medication teratogens: Soriatane

A

reasons for 3 year deferrals for blood donating

42
Q

What are these?

Needle stick or other contact with blood
Sex with person with HIV or hepatitis
Sex with IVDA
Rape victims
Incarcerated >72 hrs.
Paying for sex
Allogeneic blood transfusion
Allogeneic transplant
Living with person with active hepatitis
Receiving HBIG
Tattoos/piercings
Travel to malaria endemic area
Syphilis or gonorrhea
Non-prophylactic  rabies vaccines
Travel to Iraq
A

reasons for one year deferrals for blood donation

43
Q

T/F: Other deferrals for blood donation include pregnant women (should wait 6 mo’s postpartum), non-routine dental work (wait 72hrs), immunizations (wait 2-4 weeks), certain drugs

A

True

44
Q

What kinds of screens are done on every vial of blood that is drawn?

A 
ABO/RH
Antibody screen
Anti-HTLV
West Nile Virus
Anti-Trypanosoma cruzi
Serologic syphilis
Hep B
Hep C
HIV
45
Q

Is autologous blood donation more or less strict than allologous blood donation?

A

blood donation screening is not as strict if you are donating blood to yourself

46
Q

What is a major crossmatch? What is a minor crossmatch? Which is used more frequently?

A

major crossmatch: recipient’s serum crossed with donor RBCs;
**way more common

minor crossmatch: donor’s serum crossed with recipient’s RBCs **rare

47
Q

Whole blood can be “soft spun” into what two components?

A

platelet rich plasma and packed RBCs

48
Q

Platelet rich plasma can be “hard spun” into what two components?

A

platelet concentrates and fresh frozen plasma

49
Q

Fresh frozen plasma can be spun into what two components?

A

cryoprecipitate and plasma derivatives

50
Q

Is a transfusion expected to raise the Hct and Hb? Is a transfusion expected to raise platelet count?

A

yes (Hct by 3% and Hb by 1%; check after 15 minutes)

yes (by 20,000-30,000 in an hour)

51
Q

4 ways to modify blood in order to prevent adverse transfusion reactions? Which method is used for immunosuppressed patients? Which method is used for IgA deficiency?

A

leukoreduction (decrease WBCs in blood)
washing (effective for IgA deficiency)
freezing
irradiation (deactivates T cells; used for immunosuppressed pts)

52
Q

What is the difference b/w an acute and delayed transfusion reaction?

A

acute occurs w/i 24 hrs of transfusion; delayed occurs after 24 hrs

53
Q

Acute hemolytic transfusion reactions can be immune or non-immune. What are some signs on an immune reaction? What is one sign of non-immune reactions?

A 
abdominal, chest, or back pain
pain at infusion site
feeling of doom
hemoglobinemia/hemoglobinuria
renal failure/shock
DIC;

asymptomatic hemoglobinuria

54
Q

What type of hypersensitivity reaction is occurring in immune acute hemolytic transfusion reactions?

A

type II hypersensitivity rxn

55
Q

Acute hemolytic transfusion reactions can be intravascular or extravascular. What antibodies are usu involved in extravascular reactions? Intravascular reactions?

A

intravascular: ABO, Kidd **usu more severe
extravascular: Rh, Kell, Duffy

56
Q

What is the first step in a transfusion reaction work-up?

A

stop the dang transfusion!

57
Q

What steps should be taken after you stop the transfusion?

A

clerical check (double check the paperwork/bag/blood bank paperwork)
draw a post-transfusion sample and compare it to the pre-transfusion sample
DAT
repeat ABO/Rh testing

58
Q

Most frequently reported reaction
Unexplained increase in temperature 1ºC
Etiology: increased pyrogenic substances from WBCs
Pretransfusion: donor WBCs secrete cytokines in storage bag
During transfusion: Recipient antibodies attack donor WBCs or vice versa
Treatment
Antipyretics
Demerol

A

febrile non-hemolytic transfusion reaction

59
Q

Allergic transfusion reactions can be mild, moderate, or severe. Is it ever appropriate to restart the transfusion after such a reaction?

A

yes, in mild reactions only you may restart the transfusion after the hives clear

60
Q

Extravascular hemolysis at least 24 hours but less than 28 days after transfusion
Etiology
Anamnestic response
Antibody formed but fades over time
Anamnestic rapid production of IgG antibody
Typical for Kidd, Duffy and Kell antibodies
Primary response
Antibody is quickly formed and attacks still circulating transfused red cells

A

delayed hemolytic transfusion reaction

61
Q

Attack on recipient cells by viable T-lymphocytes in transfused blood product
Patients present with
Fever 7-10 days post-transfusion
Face/trunk rash that spreads to extremities
Mucositis, nausea/vomiting, watery diarrhea
Hepatitis
Pancytopenia
Patients at risk: all those requiring irradiation
Treatment: Irradiate blood products

A

transfusion associated GVHD

62
Q

Acute non-immune transfusion reaction
Due to bacteria in contaminated platelets and RBCs
Staph, strep, Yersinia, bacillus, pseudomonas, E. coli

A

transfusion associated sepsis

63
Q

Similar to severe allergic reaction but no skin symptoms, no GI or respiratory issues
>30mm Hg drop in systolic BP; diastolic ≤80mm Hg
Occurs

A

hypotensive transfusion reaction

64
Q

1 cause of transfusion related fatality in US

New acute lung injury ≤6 hrs. post transfusion
Associated with platelets but also RBC/WB
Two proposed methods
Neutrophils produce toxic free radicals that damage endothelial cells
Donor anti-HLA or anti-neutrophil antibodies bind to recipient antigens and damage endothelial cells

A

transfusion related acute lung injury

65
Q

1 cause of transfusion related fatality in US

A

acute lung injury (usu due to platelets)

66
Q

Acute onset of congestive heart failure as a direct result of blood transfusion

A

transfusion associated circulatory overload

67
Q

Rare
Marked thrombocytopenia and increased risk of bleeding 10 days following transfusion
Due to antibody against a common platelet antigen
Anti-HPA-1A
PLA1 has a frequency of 98%

A

post transfusion purpura

Block 7 Week 3 (5 decks)

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