Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MBBS II HIS > L26 – Transfusion beyond Immunohaematology > Flashcards

L26 – Transfusion beyond Immunohaematology Flashcards

1
Q

2 ways of grouping blood types by ABO?

A
  1. Cell grouping: presence/absence of A, B antigen(s) on the RBC’s
  2. Plasma / serum grouping: presence/absence of Anti-A &/or Anti-B in serum
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What does the ABO gene code for? Which chromsome?

A

chromosome 9.

code for enzyme with glycosyltransferase activity

> > modifies oligosaccharides on glycoproteins at surface membrane of RBC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Compare the effects of glycosyltransferace on different ABO blood groups?

A

Default oligosaccharide structure = H-antigen

A allele = adding N-acetyl galactosamine to H-antigen = A Antigen

B allele = adding galactose to H antigen = B antigen

O allele = protein with loss of transferase activity = H antigen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What type of Ig is natural Anti-A, Anti-B antibodies? Can it cross placenta?

A

IgM

active at body temperature
Cannot cross placenta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does Anti-A, Anti-B Ab cause hemolysis of incompatible RBCs?

A

Anti-A/B IgM can activate complements at body temp&raquo_space; acute intravascular hemolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Difference between natural and immune-induced Anti-A/ Anti-B Antigen?

A

Natural = IgM

Immune origin = IgG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Inheritance pattern of ABO gene?

A

Autosomal dominant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define the A,B antigen and Anti-A, Anti-B antibodies in Group O blood?

A

No A,B antigen

Have both Anti-A, Anti-B Ab

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Define the A,B antigen and Anti-A, Anti-B antibodies in Group A blood?

A

Have A antigen

Have Anti-B Ab

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define the A,B antigen and Anti-A, Anti-B antibodies in Group B blood?

A

Have B antigen

Have Anti-A Ab

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Define the A,B antigen and Anti-A, Anti-B antibodies in Group AB blood?

A

Have both A, B antigen

No Anti-A or Anti-B Ab

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

List the genotypes that correspond to A,B,AB and O group blood.

A

Group A = AA, AO
Group B = BB,BO
Group AB = AB
Group O = OO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

List 2 conditions due to ABO incompatibility

A

Acute haemolytic transfusion reaction

ABO haemolytic disease of the newborn (HDN)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Pathogenesis of acute hemolytic transfusion reaction?

A

Natural Anti-A/B Ab bind to incompatible RBC

Activate complements&raquo_space; acute intravascular haemolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Symptoms of acute hemolytic transfusion reaction?

A

 Fever

 Hemoglobinemia (free Hb)
 Hemoglobinuria (should differentiate from hematuria by urine microscopy)
 Hemosiderinuria

 DIC = multiorgan failure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Pathogenesis of ABO haemolytic disease of the newborn?

A

immune** ABO antibodies (IgG) crossing the placenta to destroy the RBC’s of the foetus

Usually group ‘O’ mothers with non-’O’ foetus

mild & self-limiting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What type of molecule is Rhesus factor?

A

transmembrane polypeptide with >50 antigenic specificities

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

List the main Rh antigenic specificities? What genes code for Rh?

A

D, C, c, E, e

2 closely linked genes: D & CcEe (CE, Ce, cE, ce)

19
Q

Which Rh factor is most tested for and most common in HK population

A

Rh (D)

99.7% / all Chinese = Rh(D) positive

20
Q

How are Rh Ab formed? Type of Ig? Cross placenta?

A

Warm-reacting IgG

Acquired after exposure to the antigen that the patient lacks

Can cross placenta

21
Q

Pathogenesis of Rh-caused HDN?

A

Rh -ve mother and Rh +ve father make Rh +ve fetus

Mother’s immune system forms Anti-Rh IgG when exposed to fetal blood

1st pregnancy not affect, but 2nd preg. with Rh+ve fetus again&raquo_space; severe HDN

22
Q

Difference between Transfusion reaction due to Rh factor and ABO incompatalibity?

A

Rh incompatability:
- immune/ IgG** Anti-Rh Ab

  • Extravascular haemolysis (like ABO incompatability) in liver, spleen
  • NO haemoglobinuria, haemoglobinemia, haemosideruria
  • Decrease** in haptoglobin
23
Q

Which type of antibody incompatibility is insignificant?

A

Cold antibodies

24
Q

List the blood bank tests for RBC and plasma?

A

Plasma:

  • Crossmatching
  • Antibody screen
  • Plasma screen

RBC:

  • Cell grouping (antigen present)
  • Red cell phenotype
  • Direct antiglobulin test (DAT)
25
Q

Principle of serum Ab screening?

A

Screen for clinically significant antibodies against non-ABO (e.g. Rh factors, Kidd, Duffy)

i.e. Anti-Rh(D) Ab positive = must not have Rh(D) naturally

26
Q

Principle of blood agglutination tests?

A

RBC + anti-serum with known blood group specificity (e.g. with Anti-A, Anti-B antibody)

> > Agglutination = RBC has antigen against Ab specified in the anti-serum

> > No agglutination = RBC does not have the antigen against Ab in anti-serum

27
Q

Difference in function between Direct and Indirect antiglobulin test?

A

Direct = detect human Ig (e.g. AutoAb, pathological) already attached to RBC*** with anti-human-immunoglobulin antibody (AHG reagent)

Indirect = Detect RBC antibodies (natural) in serum/ ABO testing with AHG

28
Q

Describe the steps in Indirect Antiglobulin Test, IAT?

A
  • Incubate serum (i.e., Ab) with RBC’s (i.e., Ag)
  • Ab will only coat the RBC’s bearing the Ag
  • Add AHG reagent to get agglutination

If the antigenic make-up of the RBC’s is known, the specificity of the Ab can be deduced

29
Q

Describe how RBC allo-antibodies are acquired? What is the response upon secondary exposure of incompatible blood?

A

acquired through sensitizing events:

  1. Pregnancy (especially labor)
  2. Transfusion

Secondary exposure = Surge of IgG cause extravascular hemolysis&raquo_space; delayed hemolytic transfusion reaction

30
Q

Compare the course of action if blood bank testing on donor serum and RBC returns positive or negative?

A

Positive = (~7%) further screen specifically to pick compatible blood

Negative = perform electronic crossmatch to select ABO blood group = give ABO, RhD compatible blood

31
Q

Which blood type is given urgently to massive blood loss?

A

Unmatched group O blood (immediate)

Unmatched ABO group specific blood (25mins to test ABO and RhD)

32
Q

Distinguish the IAT, DAT and Ab specificity results for autoimmune and alloimmune haemolytic anemia?

A

Autoimmune = Both DAT + IAT positive, Autoantibody with broad specificity

Alloimmune = positive IAT &/or DAT, Alloantibody with defined specificity

33
Q

List some causes of Warm-antibody type AIHA?

A

1) Idiopathic

2) asso. with:
 Autoimmune diseases
 Lymphoproliferative disorders (LPD)
 Drugs***

34
Q

List some causes of Cold-antibody type AIHA?

A

1) Idiopathic

2) asso. with:
 Infections*** (infectious mononucleosis, mycoplasma)
 LPD, e.g. lymphoma

3) Paroxysmal cold haemoglobinuria

35
Q

List 2 alloimmune haemolytic anemia?

A

 Haemolytic transfusion reaction

 Haemolytic disease of the newborn

36
Q

What special blood component is given to severely immunocompromised patients (e.g. after chemo/radi)?

A

Irradiated blood components: prevent transfusion associated graft versus host disease

37
Q

3 indications of Leucocyte-depleted Blood Components ?

A

– Prevention of HLA alloimmunization (long-term transfusion support or potential BMT recipient)

– Prevention of Febrile non-hemolytic transfusion reactions FNHTR (Ab vs donor WBC)

– Prevention of CMV transmission

38
Q

List 4 acute complications of blood transfusion

A
  • Acute haemolytic transfusion reaction
  • Febrile non-haemolytic transfusion rxn (Ab rxn with transfused WBC)
  • Urticaria (Ab rxn with transfused proteins)
  • Pulmonary edema

Rare:

  • Infective shock (contaminated blood)
  • Anaphylaxis, Transfusion related acute lung injury
39
Q

List 4 delayed complications of transfusion?

A
  • Delayed haemolytic transfusion reaction
  • Transfusion transmitted infections (viral mostly)
  • Iron overload
  • Ab develop to transfused WBC/ Plt
40
Q

List some ways to ensure blood safety?

A
  • Stringent donor selection criteria
  • Sensitive virological/microbiological assays
  • Comprehensive serological workup
  • Proper preparation, QC, storage conditions
41
Q

Role of doctor in ensuring transfusion safety?

A
  • The right specimen from the right patient
  • The right unit for the right patient

Positive Identification of Patient

Informed Consent in Transfusion: risk, benefit, alternatives

Transfuse the minimal amount

42
Q

3 targets of patient blood management?

A
  • Optimize Hb
  • Minimize blood loss
  • Rationalize transfusion
43
Q

Alternatives to red cell transfusion for iron deficiency anaemia?

A

Iron replacement

– Oral iron: FeSO4, Ferrum Hausman Solution

– IV iron: Venofer, Monofer

44
Q

Organization of Hospital Transfusion Service (3 parts)

A

Hospital transfusion commitee: oversees:

1) Hospital Blood Bank
2) Users of all disciplines (Medical & Nursing Staffs)

MBBS II HIS (30 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions