Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Haematology > The blood transfusion laboratory > Flashcards

The blood transfusion laboratory Flashcards

(65 cards)

Start Studying
1
Q

What are antigens a part of?

A

Antigens are part of the surface of cells

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

What are antibodies?

A

Antibodies are protein molecules(Igs)

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

What classes are antibodies usually of?

A

Usually of the Ig classes: IgG and IgM

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

Where are antibodies found?

A

Found in plasma

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

What are antibodies produced by and following what?

A

Produced by the immune system following exposure to a foreign antigen

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

How many blood groups systems are known?

A

There are 26 known blood group systems

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

What are clinically the most important blood group systems?

A

ABO and Rh are clinically most important

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

What can antigens in transfused blood stimulate but only under what circumstance?

A

Antigens in transfused blood can stimulate a patient to produce an antibody but only if the patient lacks the antigen themselves

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

What can stimulate antibody production?

A
  • Blood transfusion
  • Pregnancy
    • Fetal antigens entering maternal circulation during pregnancy or birth
  • Environmental factors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does an antibody antigen reaction in vivo lead to?

A

Leads to destruction of the cell

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

What are the 2 ways the cell can undergo destruction when an antibody and antigen react?

A
  • Directly

- Indirectly

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

Direct destruction of cell

A
  • Directly when the cell breaks up in the blood stream (intravascular)
    • Antibodies and antigens interact to cause haemolysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Indirect destruction of cell

A

Indirectly when liver and spleen remove antibody coated cells (extravascular)

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

What does antibody antigen reaction in vitro lead to?

A

Reactions are normally seen as agglutination tests

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

What is agglutination?

A

Agglutination is the clumping together of red cells into visible agglutinates by antigen-antibody reactions

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

What does agglutination result from?

A

Agglutination results from antibody cross-linking with the antigens

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

What can agglutination identify?

A
  • Presence of a red cell antigen

- The presence of an antibody in plasma

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

What is the clinical significance of the ABO grouping system?

A
  • A and B antigens very common (55% UK)
  • Anti-A, anti-B or anti-A,B antibodies very common (97% UK)
  • High risk of A or B cells being transfused into someone with the antibody in a random situation
  • ABO antibodies can activate complement causing intravascular haemolysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Steps involved in blood grouping

A
  • The patient’s red cells and plasma are both tested
  • Test patient’s red cells with anti-A, anti-B and anti-D
    - Agglutination shows that a particular antigen is on the red cells
    - No agglutination shows the antigen is absent

Test patient’s plasma with A cells and B cells

      - Agglutination shows that a particular antibody is in the plasma or serum 
      - No agglutination shows the antibody is absent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the most important antigen in the RH grouping system?

A

Most important antigen is called D.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are people with D antigen in terms of RHD?

A

People with D antigen are RhD positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are people who don’t produce D antigen in terms of RHD?

A

People who do not produce any D antigen are RhD negative (15%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the other 4 main antigens in the RH grouping system known as, other than D?

A

The other 4 main Rh antigens are known as C, c, E and e

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How must RH D typing be tested?

A

Must be tested in duplicate (or tested each time and compared to historical result)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Clinical significance of RH antibodies in transfusion?
Transfusion - D antigen is very immunogenic and anti-D is easily stimulated - PREVENTION! - All Rh antibodies are capable of causing severe transfusion reaction- ANTIBODY DETECTION
26
Clinical significance of RH antibodies in pregnancy
- Rh antibodies are usually IgG and can cause haemolytic disease of the newborn. - Anti-D is still most common cause of severe HDN
27
What happens in the haemolytic disease of the new born(HDN)?
1. We have a RH+ father 2. RH- mother is carrying her first RH+ fetus. RH antigens from the developing fetus can enter the mother's blood during delivery 3. In response to the fetal RH antigens, the mother produces anti RH antibodies 4. If the woman with becomes pregnant with another RH+ fetus her anti RH antibodies will cross the placenta and damage fetal red blood cells
28
Why do we screen blood groups and antibodies at antenatal booking?
Blood group and antibody screen at antenatal booking to identify pregnancies at risk of HDN
29
At what week do we carry out blood group and antibody screening
Blood group and antibody screen at 28 weeks
30
Why are atypical antibodies quantified periodically?
Atypical antibodies are quantified periodically to assess their potential effect on the fetus
31
What is RAADP and what does it do?
An injection of anti-D and will bind to and remove any fetal RhD positive red cells in the circulation
32
What are RBCs unable to do when bound to anti-D?
If red cells bound, they wont be able to stimulate mothers immune system
33
Dosage of anti D
1500 iu of anti-D is given routinely at 28 weeks and a smaller dose
34
What events is anti-D also given after?
Anti-D is also given after any event that may cause a feto-maternal haemorrhage (bleed between mum and fetus) such as: - Abdominal trauma - Intrauterine death - Spontaneous or therapeutic abortion
35
What is reverse grouping of blood?
Looks for corresponding antibodies for the antigens in the plasma
36
Steps involved in reverse grouping of blood
1.Patients serum is mixed with 3 selected screening cells - Screening cells that have on them the relevant antigen that would cause a problem if a transfusion was given blind 2. Incubated for 15 minutes at 37c 3. Centrifuged for 5 minutes 4. Any clinically significant antibodies reacting at body temp should be detected and then identified using panel of known phenotyped red cells 5. Specific antigen negative blood can then be provided for these patients to avoid stimulating an immune response
37
What must we do if antibody is detected in reverse grouping of blood?
- Identify the antibody - Assess its clinical significance - For transfusion - In pregnancy
38
How do you identify an antibody?
- Compare pattern of reactions with each reagent cell of ID panel with the pattern of antigens on the reagent cells - Matching pattern will identify the antibody
39
What is zeta potential?
Positively charged ion cloud that surrounds RBC
40
Why are RBCs unable to get close to one another?
Red cells cannot get close to each other due to the zeta potential
41
What class of antibodies can span the gam between RBCs?
IgM antibodies can span the gap between RBCs | -Doesn’t need LISS
42
What class can not span the gap between RBCs and so what do we use in order for this class of antibody to span the gap?
IgG cannot, because too small to overcome ZETA potential (+ve charge) - To overcome this LISS (Low Ionic Strength Saline) is used - LISS (low ionic strength saline) is negatively charged, so neutralises positive ZETA potential - Therefore IgG can now span the gap
43
What does indirect anti-globulin test(IAT) detect?
Used to detect IgG antibodies
44
Steps involved in IAT?
1. LISS counteracts Zeta potential. | 2. Results in agglutination
45
What is IAT used for?
1. Screening for antibodies 2. Identifying antibodies 3. Cross-matching donor blood with recipient plasma when there are known antibodies or a previous history of antibodies.
46
Immediate spin cross-match
- Antibody screen is negative - Checking donor red cells against patients plasma - ABO check - Incubate for 2 – 5 minutes (room temp), spin and read
47
Full indirect antiglobulin test cross match
- Antibody screen positive or patient has known antibody history - Select antigen negative donor red cells and incubate with patient serum for 15 minutes at 37oC
48
ISX-basically checking the ABO group
Therefore IgM antibodies = no problem with ZETA potential = no need to IAT
49
How many donations does the NHSBT collect?
NHSBT collects about 2 million donations per year
50
What is the eligibility for blood donors?
- 17 - 65 years old (first donation) | - Over 50kg
51
What are concentrated RBCs packed in?
Concentrated red cells (packed cells) in a suspension of SAGM
52
What do we activate if there's significant bleeding?
If significant bleeding anticipated, activate the major haemorrhage protocol
53
What does fresh frozen plasma contain?
FFP contains all clotting factors
54
What is FFP given for?
Given for coagulopathy with associated bleeding
55
What is FFP life after thawing?
Only has 24 hour life after thawing
56
How many donors is an adult pool of platelets from?
Adult pool of platelets from 4 donors (suspended in plasma from 1 donor)
57
What are platelets required to create?
Platelets required to create clots to reduce bleeding
58
Why is patient history important in terms of platelets?
Some drugs given to reduce efficacy of platelets (anti-platelet agents) so patient history important
59
What does cryoprecipitate contain?
Contains Factor VIII, VWF and fibrinogen
60
How many units of cryoprecipitate is given at one time?
2 units usually given at one time
61
What do we use to monitor fibrinogen levels?
Monitor fibrinogen levels by clotting screens
62
Regulation of blood
EU Blood Safety Directive Blood Safety Quality Regulations Better Blood Transfusion 3 MHRA inspections CPA inspections
63
What is hemovigilance?
Surveillance procedures covering the entire blood transfusion chain
64
Serious hazard of transfusion(SHOT)
- Voluntary reporting | - Report all Serious adverse Events (SAE) and Serious adverse reactions (SAR)
65
Serious adverse blood reactions and events(SABRE)
- Mandatory reporting | - Report all SAR and SAE where the root cause error was the Quality system

Haematology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions