TRANSFUSION Flashcards
what are the minimum criteria for blood donors
Hb - 135 g/L men - 125 g/L women weight - 50 kg
donated blood is tested for which infections
HIV
Hep B/C/E
HTLV
syphilis
how are red cells stored
4 degrees for 35 days
how is FFP stored
-30 degrees for 3 years
how are platelets stored
22 degrees for 7 days with agitation to prevent clotting
what its he deference between blood components and blood products
blood components come from a single donor
blood products are combined from as many as 200 donors
what are red cell components
red cells
FFP
platelets
cryoprecipitate
examples of blood products
anti-D Ig prothrombin complex concentrate IV Ig human albumin specific Ig
what are the two most important blood group systems
ABO
Rh
which chromosome is responsible for producing the antigens of the ABO system
chromosome 9
what do the A and B genes on chromosome code for
transferases which modify precursor called H substance on red cell membranes
what is the most common ABO blood type
O
what is the least common blood type
AB
what does Landsteiner;s law state
when an individual lacks the A or B antigen the corresponding antibody is produced in their plasma
how does the body produce antibodies to the lacking A or B antigen
bacteria express similar antigens on their membranes which causes the body to produce anti-A or anti-B antibodies
what effect do anti-A or anti-B antibodies have on red cells
cause haemolysis if red cells express that antigen
which antibodies are present in a person with type A blood
anti-B
which antibodies are present in a person with type B blood
anti-A
which antibodies are present in a person with type AB blood
neither
which antibodies are present in a person with type O blood
anti-A and anti-B
people with type O blood can receive donor blood from which groups
O
people with type A blood can receive donor blood from which groups
O
A
people with type B blood can receive donor blood from which groups
O
B
people with type AB blood can receive donor blood from which groups
O
A
B
AB
is the majority of the population Rh positive or negative?
Rh positive
why is the Rh system important
it is very immunogenic
it can cause transfusion reactions and haemolytic disease of the foetus and newborn
how can individuals become sensitised stocks exposure to foreign antigens
pregnancy
transfusion
what is antisera and why is it used
reagents with known antibody specificity to identify antigens present on the red cell
what are reagent red cells are why are they used
red cells with known antigen specificity to identify antibodies present in the plasma
how is ABO/D grouping carried out
patients red cells are tested with anti-A, anti-B and anti-D antisera
(identify antigens on red cells)
patient’s plasma is tested against reagent red cells of group A and group B
(identify antibodies in the plasma)
how is the presence of other antibodies in the plasma tested for
indirect antiglobulin test
- reagent red cells expressing known antigens
- add patient plasma
- add anti-human globulin
- look for agglutination
how does anti-human globulin show the presence of antibodies in a patient’s plasma
it binds to antibodies that are bound to red cells to cause agglutination
i.e. only causes agglutination if there are other antibodies present in the plasma
how is donor blood crossmatched with patient blood
patient plasma is added to donor red cells
anti-human globulin is added
look for agglutination
what are indications for red cell transfusion
symptomatic anaemia (Hb <70 g/L0 major bleeding
indications for platelet transfusion
prophylaxis in patients with bone marrow failure and very low platelet counts
treatment of bleeding in thrombocytopaenic patient
prophylaxis prior to surgery/procedure in thrombocytopaenic patient
indications for FFP transfusion
treatment of bleeding in patient with coagulopathy
prophylaxis prior to surgery or procedure in patient with coagulopathy
management of massive haemorrhage
transfuse early in trauma
what monitoring should be carried out during transfusion
observations before blood transfusion
observations at 15 minutes
observations within 60 minutes of completion
