FHMP 030 Blood components and blood groups Flashcards
1
Q
what is haemopoieses?
A
- the process by which blood cells are produced
- all made from multi-potent cells in the bone marrow (haemopoietic stem cells HSC)
- HSC initially divide to produce multi-lineage progenitor cells, which then further divide and produce more mature progenitor cells until we have multiple lineages of different blood cell types
2
Q
where does haemopoiesis occur in foetus’ and adults?
A
- foetus = liver
- adult = bone marrow
3
Q
what factors regulate haemopoiesis?
A
- growth factor = granulocyte-colony-stimulating factor (G-CSF) acts on the progenitor and precursor cells in the bone marrow which give rise to neutrophils
- accessory cells = adipocytes, fibroblasts, osteoblasts, osteoclasts and endothelial cells
4
Q
what are erythrocytes/what do they do?
A
- red blood cells
- transport oxygen from lungs to tissues and carries away carbon dioxide to the lungs to expire
- contain haemoglobin which oxygen binds to
5
Q
what are immature red blood cells called?
A
- reticulocytes
- comprise of 1% of erythrocyte count
- through erythropoiesis, reticulocytes develop and mature in the bone marrow and then circulate for about a day in the blood stream before developing into erythrocytes
6
Q
how are red blood cells stored?
A
- as reticulocytes
- 280ml in a unit
- 3ml/kg increases the Hb by 10g/L
- stored at 4 degrees for up to 35 days
- Red cells are suspended in a fluid medium called additive solution
7
Q
what are leukocytes and what are the 5 types of leukocytes?
A
- white blood cells
- neutrophils
- basophils
- eosinophils
- monocytes
- lymphocytes
8
Q
what are the 3 granulocytes?
A
- neutrophils, basophils, eosinophils
- because they contain granules in their cytoplasm
9
Q
what are basophils and what is their function?
A
- white blood cell, leukocyte, granulocyte
- least common of the granulocytes
- responsible for inflammatory reactions and allergic responses
- undergo phagocytosis
- produce histamine, serotonin and heparin
10
Q
what are neutrophils and what is their function?
A
- most abundant type of granulocyte and leukocyte
- short lived and highly motile
- part of innate immune response
- undergo phagocytosis of the pathogens/microorgansims
11
Q
what are lymphocytes and what is their function?
A
- main cell type found in lymph
- comprised of B and T lymphocytes
- recognise foreign cells/ infected cells and kill them
- help antigen presentation and produce antibodies and memory cells
12
Q
what are monocytes and what is their function?
A
- largest type of leukocyte
- differentiates/matures into macrophages which can phagocytose
- present antigens
- in blood stream but macrophages found in tissues
13
Q
what are eosinophils and what is their function?
A
- type of granulocyte
- responsible for combating multicellular parasites and certain infections
- also respond to allergy
14
Q
what are thrombocytes and what is their function?
A
- platelets
- help stop bleeding by clumping and clotting blood vessel injuries
- have no cell nucleus
- are fragments of cytoplasm that are derived from the megakaryocytes of the bone marrow and then enter the circulation
15
Q
how are thrombocytes stored?
A
- stored at 22 degrees and constantly agitated so dont clump
- store for 7 days (risk of bacteria infection)
- need to know blood group but crossmatch is not needed
16
Q
what is plasma, what is it made up of and its function?
A
- largely made in the liver
- makes up 55% of blood volume
- contains plasma proteins like fibrinogen, albumin, immunoglobulins and clotting factors
- fibrinogen = helps with clotting
- albumin = helps regulate oncotic pressure of the blood
- immunoglobulins = antibodies, kills pathogens
- clotting factors = help speed up the clotting process
17
Q
what are the 2 ways to store plasma?
A
- fresh frozen plasma (FFP)
- cryoprecipitate
18
Q
what is fresh frozen plasma and how is it stored?
A
- frozen and preserved plasma after a blood donation
- 1 unit = 300ml
- stored at -30 degrees for 1 year
- must use within 1 hour of thawing
- need to know blood group but dont need to crossmatch
19
Q
what is cryoprecipitate and how is it stored?
A
- when fresh frozen plasma is centrifuged and the precipitate is collected
- stored at -30 degrees for a year
- contains fibrinogen and factor VIII
20
Q
what are the 4 main blood groups?
A
- A, B, AB, O
- based on red blood cell surface antigens
21
Q
describe the inheritance of ABO blood groups
A
- A and B are co-dominant
- O is recessive
22
Q
describe the differences in the blood group antigens and antibodies
A
- group A = A antigen and anti-B
- group B = B antigen and anti-A
- group AB = A and B antigen and no antibodies
- group O = no antigens and anti-A and anti-B
23
Q
what is the Rhesus (Rh) blood group?
A
- 2 genes code for the RhD groups
- D is dominant coding for D antigen
- d is recessive coding for antigen
- So RhD positive = with antigen and RhD negative = no antigen
- 85% of people are RhD Positive
24
Q
Name 5 blood group related clinical scenarios
A
- haemolytic disease of the newborn
- acute haemolytic transfusion reaction
- delayed haemolytic transfusion reaction
- non-immune transfusion reactions (not blood group related)
- major haemorrhage
25
what is haemolytic disease of the newborn?
- when a mother is RhD- and the baby is RhD+
- first child/birth is fine but during birth, the transfer of foetal blood to maternal blood sensitises mother's blood and produces anti-D antibodies
- the following pregnancies will cause the anti-D antibodies to attack the foetus' erythrocytes, causing HDN
- leads to bilirubin release, causing neonatal jaundice and can lead to permanent brain damage (kernicterus) if bilirubin is deposited there
26
how is haemolytic disease of the newborn treated?
- RhIG (Rh immunoglobulin, antibodies to Anti-D) is given to the mother at 28 week and 34 weeks and 48 hours after delivery to prevent sensitisation of the mothers blood to RhD+ antigens (in first pregnancy and everyone after)
27
what is acute haemolytic transfusion reaction?
- most serious and life-threatening
- usually ABO incompatibility
- very rare and lethal
- causes anaphylaxis, like an allergic reaction
28
what is delayed haemolytic transfusion reaction?
- incompatibility with blood groups other than ABO e.g. Rhesus
- causes anemia and jaundice
- less severe usually
29
give 3 examples of non immune transfusion reactions ( not blood group related)
- infection e.g. bacteria
- iron overload = a major cause of morbidity and mortality in people with transfusion-dependent diseases due to iron deposits in the liver
- errors = human error when administrating the transfusion - need to have name, DOB, hospital number and signed by the patient to be correct and label patient
30
what are some special considerations to take into account when doing transfusion?
- age of blood, younger blood lasts longer, less cation leak
- specific phenotype requests e.g. for sickle and thalassemia
- irradiated - may have depressed lymphocyte function e.g. due to certain drugs or condition e.g. di George syndrome
- haemoglobin count, plasma depleted
31
what is a major haemorrhage?
- when someone has a haemorrhage that becomes hypotensive
- loss of more than 1 blood volume in 24 hours (70ml/kg)
- 50% of total blood volume lost in less than 3 hours
- bleeding in excess of 150ml/min
32
what is the major haemorrhage protocal?
- call haematology register/ consultant, blood bank, and courier to get blood as soon as possible
- patient is given fresh red blood cells and fresh frozen plasma otherwise just red cells the patient would become coagulopathic (cannot clot blood)
- full cross match takes too long (45 minutes), so whilst waiting, give universal O Rh- blood (no antigens to react to)
33
what are the 2 antiglobulin tests?
- direct antiglobulin test (DAT)
- indirect antiglobulin test
34
what is the direct antiglobulin test and what does it test for?
- testing if there are any antibodies on the patient's erythrocytes
- detects the cause of haemolytic anaemia, investigates transfusion reaction and diagnoses haemolytic disease of the newborn
- also known as the Coombs test
- adds anti-globulin to patients red blood cells
- if present the red blood cells will clump together (agglutination)
35
what is the indirect antiglobulin test and what does it test for?
- tests for antibodies in the patients serum
- detects antibodies against red blood cell antigens, in preparation of a transfusion or during pregnancy/birth
- o
