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28 Cards in this Set
- Front
- Back
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What are the 4 ABO phenotypes of blood? |
A AB B O |
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What dies the ABO gene encode for? |
ABO gene encodes for glucotransferase. i.e It is this gene that determines which sugar is stuck onto the plasma cells. A has a different sugar stuck onto it than B. O has no sugar stuck onto it. Under the control of H and h alleles. |
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Explain the ABO antigen blood group system?
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The cells and proteins in blood express antigens which are controlled by an individuals genes. The blood group of an individual is determined by which antigens are stuck onto the the RBCs. The blood group system involves naturally occur ing IgM anti-A and anti-B antibodies. It is only when you come across another blood group e.g Blood transfusions then the body mounts an IgM mediated response against it = Heamolysis. |
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What is the difference between anti bodies and antigens? |
Antibodies are like the security guards which recognise anything that is foreign. Antigens are the burglars which identify themselves as invaders. ie. An antibody lets its own type in, but an antigen reveals itself as foreign. So antibodies are constantly looking for antigens. |
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What are the anti bodies and antigens which lie on the surface of A, B and O groups? |
A group = Has antiB antibodies and A antigens. B group = Has antiA antibodies and B antigens. O group = Has A and B antibodies but no antigens. AB group = Antibodies cancel each other out so no antibodies, has A and B antigens *think of it like, A can detect B and B can detect A but neither can detect O. O can detect A & B. AB group is like A and B has teamed up so they have no antibodies cus they like each other and but have A & B antigens* |
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Which blood group is the universal donor? |
O is the universal donor. This is because it has no antigens and so cant be detected by A or B groups. |
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Which blood group is the universal receiver? |
AB is the universal receiver. This is because it has no antibodies so can receive from anyone. |
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What is the difference between RBCs and plasma in terms of antigens and antibodies? |
Plasma has no antigens but has antibodies. So nobody can detect them but they can still detect the wrong blood. |
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Which blood group is the universal receiver of plasma? |
Blood group O is the universal receiver of Plasma. Because plasma has no antigens then it cannot be detected by blood group O because it itself has no antigens. |
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Which blood group is the universal donor of plasma? |
AB - because it has no antigens it can get past the antibodies lack of antibodies in AB. |
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What percentage of europeans are Rhesus negative? |
15% of europeans are rehsus negative. |
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Can rhesus negative patients receive from Rh + patients? |
If Rhesus negative is exposed to Rh+ then it will make anti - Rh+ antibodies. Will mount a IgG reaction. |
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What is the rule for Rh + and Rh - blood donation? |
People who are Rh + can receive blood from anyone and but can only give to positive. People who are Rh - can only receive from other Rh- but can give to anyone. |
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What are the blood vs. plasma compatibility that the ABO blood groups can accept? |
Blood: A = A, O B = B, O AB = A, B, AB, O O = O *O universal giver, AB universal receiver Plasma: A = A, AB, O B = B, AB, O AB = AB O = A, B, AB, O *AB universal giver of plasma, O is universal receiver *only positives can give to positives but negatives can give to all* |
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What are the 3 main components of blood? |
Blood can be broken down into: Red cells Platelets Plasma |
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What are the indications for giving a Red cell blood transfusion? |
Given when the patient is low on RBCs so: Anaemia Blood loss Surgery Bone marrow failure Chemotherapy Sickle cell anaemia Thalassemia |
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What is the main contraindication for transfusing plasma? |
Plasma is most useful for massive haemorrhages. |
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If a patient has an antigen mounted reaction to the blood transfusion then what test would you perform? |
Coombs test - looks for specific antibodies by introducing anti human globulin and seeing if it reacts. Direct used to test for Auto-immune haemolytic anaemia. Indirect used to test for antibodies in blood before transfusion. |
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According the the SHOT database of blood transfusion events, what is the most common error? |
The most common error is putting the wrong type of blood in a patient. e.g giving O patient AB blood |
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What is the minor and major reactions that occur in patients who have received the wrong blood group? |
Minor: Fever and Uricarial Rash Major: Fever, urticaria - aka Hives - treated with antihistamines respiratory distress (lack of RBCs because they are all being broken down), hypotension, tachycardia (heart is having to work harder to get few RBCs round quicker), oliguria (kidneys trying to get rid of blood quick) bleeding (heamolysis), Collapse - can be fatal. |
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What is the correct response to a patient who has just undergone a blood transfusion with blood that does not match? |
Slow down transfusion and then stop. |
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If the patient has a major reaction to being given wrong blood type then they will experience anaphylaxis, what are the signs and what is the treatment for a patient who has undergone anaphylaxis shock? *most commonly occurs when giving plasma not RBCs* |
Signs: Wheeze, raised pulse, low BP, laryngeal and facial oedema Treatment: O2, IM adrenaline, bronchodilator, fluid, IM hydrocortisone, antihistamine *in all cases of problems SHOT report should be notified* |
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Beyond anaphylactic shock, what is the other major complication that can occur in blood transfusions? |
Transfusion Associated Circulatory Overload (TACO) Caused by giving the fluid too quickly. Treatment = Slow the rate, IV diuretics, O2 |
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What is the signs that the patient has received the wrong ABO group and they are experiencing rapid heamolysis ? |
Signs: Shock, high fever, renal failure, resp. distress, collapse Treatment: O2, IV diuretics, iontropes, dialysis *notify SHOT* |
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What are the circumstances that cause a mother to create Anti D antibodies against her baby? |
If the baby is Rh + and the mother is Rh - then the mother will create anti D antibodies against it. Thats becuase Rh + is the dominant allele and so it isn't welcomed by Rh -. *if it was the other way round and the mother was Rh + but baby Rh - then it wouldnt matter becuase Rh + always wins* |
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At what point would a mother mount an anti D immune response against a Rh + baby? |
In 3rd trimester or birth mother is at risk of creating antibodies against Rh + babies. This is possible because it is an IgG mounted response so it can cross the placenta. |
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Why doesn't ABO group differences between mother and baby create an immune responses? |
Because the immune response mounted in ABO groups is IgM and IgM can't cross the placenta. |
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What is the treatment to prevent mothers who are Rh - attacking their own baby? |
Anti D prophylaxis at 28/40 weeks. Or before that if there is an accident which may be causing bleed in womb. |
