blood types and transfusions Flashcards
what did James Blundell do
he was the first person to transfuse blood from one human to another in 1667
what did Jean Denis do
transfused blood from animals to humans in 1666
what did Karl Landsteiner do
discovered ABO blood groups
how are blood groups classified
based on the presence of specific antigens and antibodies
what are the 4 major types of blood groups
A - more common than B
B
AB - most rare
O - most common
what is the rarest blood group
AB
what is the most common blood group
O
is blood group A more common or blood group B
A
what determines your blood group
the synthesis of genes for the A antigen or B antigen
what do people who have neither the gene that results in the synthesis of A antigen OR B antigen
O-type erythrocytes.
what antibodies do type A people have
Type A individuals always have anti-B antibodies in their plasma.
A ANTIGEN IS CO-DOMINANT
what antibodies do type B people have
Type B individuals always have anti-A antibodies in their plasma.
B ANTIGEN IS CO-DOMINANT
what antibodies do type AB people have
neither anti-A or anti-B antibodies in their plasma,
has A + B antigens on surface of red blood cells - UNIVERSAL RECIPIENT
what antibodies do type O people have
have both anti-A & anti-B antibodies ( has no A or B antigens) in their
plasma [type O is a UNIVERSAL DONOR since don’t have A or B antigens on
surface of red blood cell]. O antigen is RECESSIVE
what antibodies do type O people have
have both anti-A & anti-B antibodies ( has no A or B antigens) in their
plasma [type O is a UNIVERSAL DONOR since don’t have A or B antigens on
surface of red blood cell]. O antigen is RECESSIVE
which blood group is regarded as the universal donor and why
O
because it does not contain any antigens
which blood group is regarded as the universal recipient and why
AB
because it does not contain any antibodies
what should you look at when focusing on the recipient
their antibody
what should you look at when focusing on the donor
their anitgen
what would happen is a type A person was transfused type B blood
1) the anti-B antibodies in the
recipients blood would attack the transfused blood
and
2) the anti-A antibodies in the
donor blood would attack the recipients blood HOWEVER this is usually of little
consequence since the the transfused antibodies become so diluted in the
recipients plasma that they are ineffective at inducing a response - it is the
destruction of the TRANSFUSED cells by the recipients antibodies that produces
problems
what are rhesus antigens
transmembrane proteins expressed at the surface of erythrocytes. They appear to be used for the transport of CO2 and/or ammonia across the plasma membrane.
what are the 5 main rhesus antigens
5 main Rh antigens on red cells – C, c, D, E, e. The most important of these is the Rh D.
why is rhesus D most important
Having the D antigen on the red cell gives you the positive (+) and lacking it gives you the negative (-) after the letter A, B, AB or O.
what does Rh+ mean
contains D-antigen, no antibodies
can receive from both Rh+ and Rh-
only donates to Rh+
what does Rh- mean
contains no antigens, and anti-D antibodies
can donate to both Rh- and Rh+
only receives from Rh-
what are anti D antibodies
Unlike anti-A and anti-B, these are not naturally occurring
An Rh- individual will only produce anti-D antibodies when exposed to Rh+ blood
how are ABO antigens inherited
in a mendelian pattern
each group has a 25% chance of production
at what ages can you donate blood
17-65
what does questionnaire for donors do
highlights those at risk of infectious or transmissible illnesses
takes health, lifestyle, travel, medical history, medications
makes sure body weight is above 50kg
test for anaemia in certain patients
what can cause temporary exclusion from donating blood
travel
tattoos
lifestyle
what can cause permanent exclusion from donating blood
certain infectious diseases
ever received a blood transfusion or organ/tissue transplant since 1980
notified at risk of vCJD
what are the 2 types of donations
- whole blood
- apheresis - blood is removed and separated externally and then the components not needed are returned
what are homologous transfusions
involves someone collecting and infusing the blood of a compatible donor into him/herself
(emergency)
what are autologous tranfusions
the collection of blood from a single patient and retransfusion back to the same patient when required
what are the mandatory tests on donations
Hep B
HIV
Hep C
Syphylis
Human T cell lymphotropic virus
Groups and antibodies
what are the non-mandatory tests on donations
CMV
Malaria
West Nile Virus
Trypanosoma
how are red cells stored
at 4 degrees
shelf life of 35 days
some units will be irradiated - to eliminate the risk of transfusion-associated graft vs host disease
how are platelets stored
at 22 degrees with continuous agitation
7-day shelf life if they are monitored for bacterial contamination
is plasma from female donors kept
no
only male donors
and patients born after 1996
how to ensure safe delivery of blood
patient identification
2 sample rule
hand written patient details
blood selected and serologicaly cross matched
what are the most common patient identification errors
wrong blood in the wrong tube
lab errors (less common)
what mistakes can happen when delivering blood
blood transfusions delayed
too much blood transfused
what causes TRALI (transfusion related lung injury)
AB in donor blood reacting with recipient pulmonary endothelium/neutrophils
inflammatory cells cause plasma to leak into alveolar spaces
symptoms
- SOB
- cough productive of frothy sputum
- hypotension
- fevers
what causes TACO (transfusion-associated circulatory overload
acute or worsening pulmonary oedema within 6 hours of transfusion
one of the most common adverse risks of trasfusion
older patients more at risk
symptoms:
- respiratory distress
- evidence of positive fluid balance
- raised blood pressure
careful assessment of transfusion need and limiting amount can help to avoid
what causes bacterial contamination
more often with platelets
occurs very soon after transfusion started
symptoms:
- fevers and rigors
- hypotension
- shock
inspection of the unit may show abnormal coloration/ cloudiness
what causes haemolytic reactions
most serious ABO incompatibility
- rapid intravascular haemolysis
- cytokine release
- acute renal failure and shock
- disseminated intravascular coagulation
- can be rapidly fata
what is cross matching
-test to see if the donor’s blood is safe for the recipient
-recipient serum is mixed with the donor’s blood
-if blood is not safe –> transfusion reaction (rejection)
