Haematology Flashcards
What are the 3 components of whole blood
Red Cells
Platelets
Plasma
What are the 3 types of plasma used for blood transfusions
Fresh Frozen Plasma (FFP)
Cryoprecipitate
Plasma for fractionation
What 3 components can be collected from plasma fractionation
Albumin
Coagulation factors
Antibodies
What are the 3 cellular components of blood
Red Cells
White Cells
Platelets
Where are the cellular components of blood mainly produced
Bone Marrow
How many ml of RBC are in a unit for blood transfusions
280ml
What temperature are RBC stored at
4 degrees C
How long can RBCs be stored for
35 days
What is the name of the fluid medium used to store RBCs
Additive fluid
What are is the alternative name for Red Blood Cells
Eurythrocytes
What is the alternative name for platelets
Thrombocytes
How are thrombocytes obtained
From pooling platelets extracted from whole blood donations
How many Donors = 1 Pool
4 Donors
What is aphaeresis
Cell Separator machine used to obtain thrombocytes
What temperature are platelets stored at
room temperature
What is done to prevent platelets from clumping together
They are agitated on a plate
How long do platelets last, and why not longer
7 days, due to risk of bacterial infection
What is required and not required when transiting platelets
Correct blood group, no crossmatching required
Where are the plasma components of the blood made
liver
What are the 3 plasma components of blood
clotting factors
albumin
immunoglobin
What is FFP used for
Good source of coagulation factors
What is required and not required when administering FFP
Same blood group, no cross-match required
How much is one unit from one donor
300ml
what temperature is FFP stored at
-30 degrees C
how long can FFP be stored for
up to 1 year
How long does it take to thaw FFP
20-30 minutes
FFP must be given ASAP, why
coagulation factors degenerate over time
What is the average dose of FFP in ml/kg
12-15ml/kg
How is cryoprecipitate obtained, and why is it obtained in this way
by thawing plasma slowly to precipitate out the higher molecular weight proteins in the plasma
what temperature is FFP defrosted to obtain cryoprecipitate, and for how long
4-8 degrees C overnight
What are 2 examples of higher molecular weight proteins in plasma
Fibrinogen
Factor VIII
What are Cryoprecipitate a source for during haemorrhage
Fibrinogen
What temperature is cryoprecipitate stored at
-30 degrees C
How long is Cryoprecipitate stored for
1 Year
What is the standard dose of cryoprecipitate
10 donors
What are the 2 indications where cryoprecipitate should be used
Massive bleeding, where fibrinogen is low
Hypofibrinogenaemia (Rare)
What are the three blood groups
A
B
O
Blood groups are …… on the blood cell surface
antigens
What type of inheritance are blood groups A and B
Co-dominant
What type of inheritance is Blood group O
Recessive
What determines the antigens on the red cell surface
Genetically determined, occur through the presence/absence of certain enzymes acting on the O antigen
What blood group does a person with only the Gal Transferase enzyme have
B
What blood group does a person with the GalNAc Transferase enzyme have
A
What blood group does a person with both GalNAc and Gal Transferase enzymes have
AB
What blood group does a person with neither the GalNAc and Gal transferase enzymes have
O
How how long before birth do ABO antibodies form
3-6 months
What type of antigen are the ABO antibodies, and what 2 things can they do
IgM
Agglutinate
Activate compliment
What 2 things are unusual about the ABO antibodies
They are naturally occurring
Develop antibodies to antigens you don’t have
What are the antigens on Red cells in blood group A
A
What are the antigens on Red cells in blood group B
B
What are the antigens on Red cells in blood group AB
A and B
What are the antigens on Red cells in blood group O
None
What antibodies are present in plasma for those with blood group A
Anti-B
What antibodies are present in plasma for those with blood group B
Anti-A
What antibodies are present in plasma for those with blood group AB
None
What antibodies are present in plasma for those with blood group O
Anti-A and Anti-B
Which blood group is the universal recipient
AB
Which blood group is the universal donor
O
What percentage of people are Rhesus positive
85%
What percentage of people are Rhesus negative
15%
What determines Rhesus positive/negative
Two Genes, D and d
Which alleles code for Rhesus positive
DD or Dd
Which alleles code for Rhesus negative
dd
What 2 things are anti globulin tests used for
Cross-matching to ensure donor compatibility
Investigate haemolysis
What two things are a Direct Antiglobulin Test (DAT) used for
To detect the cause of haemolytic anaemia investigator transfusion reaction
Diagnose haemolytic disease in a newborn
What is a Direct Antiglobiuin test also know as
Coombs Test
What does the DAT determine
If there are any antibodies on the red cell surface
What happens during a DAT
Anti-globulin is added to the patient red cells
Red cell aggregation occurs is antibodies are present on the red cell surface
What is the Indirect Antiglobulin test used to detect
Antibodies directed against red blood cell antigens
What 2 things is an Indirect Antiglobulin test used in preparation for
Blood Transfusion
Pregnancy
What temperature are the test RBC incubated at during an IAT
37 Degrees C
Why is Antiglobulin added during a DAT or IAT
To detect any antibody present on the red cell surface
How is the Indirect Antiglobulin test performed
Patient serum containing antibody is added to test RBCs
These are incubated at 37 Degrees C
Antiglobulin is added to see for agglutination
During an DAT or IAT, what does agglutination mean
Red Cells are coated with a particular antibody
What are the 2 main functions of the coagulation system
Control of bleeding
Allow vessels to be repaired
What is primary Haemostasis
Formation of platelet plug and vasoconstriction
What is secondary haemostasis
Coagulation factors are activated, and thrombin in generated
What does thrombin convert fibrinogen into
fibrin
What stabilises the soluble clot formed by fibrin
Factor XIII (8)
What process breaks down fibrin
fibrinolysis
What are the 5 steps in primary haemostasis, starting from injured blood vessel
Injured Blood Vessel Exposure of collagen Platelet adhesion Activation and degranulation of platelets aggregation of platelets
What is von Willebrand factor used for
Platelet adhesion
What are the 3 stages of secondary haemostasis
Initiation
Propagation
Amplification
What 3 conversions happen during initiation
Factor VIIa and Tissue Factor combine to form TF-VIIa complex
TF-VIIa complex converts IX to IXa
TF-VIIa complex converts X to Xa
What 3 conversions happen during propagation
Factor XI converted to XIa
XIa converts IX to IXa
IXa and VIIIa convert X to Xa
What 2 conversions happen during amplification
Xa converts II to IIa
IIa converts fibrinogen to soluble fibrin