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| What
Are Blood Groups? |
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Every donor's blood belongs to one of
the four main groups A, B, AB and O, known
as the ABO system. These groups depend
for their identification on the presence
or absence of chemical substances called
antigens on the person's red blood cells.
After the ABO system,
the most important is the Rhesus system
or RH system. The RH groups are more complicated,
but most donors can be simply classified
as Rh Positive or Rh Negative.
As each system is inherited
independently of the other, it means that
there are eight main blood
groups: A+, A-, B+, B-, AB+, AB-, O+ and
O-.
The Giver/Receiver chart
below shows the compatibility of different
blood groups. From this you can see that
O- blood is the universal donor while
AB+ is the universal receiver. |
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| Blood
Compatability: |
| Group |
Donate
to: |
|
Group |
Receive from: |
| A+ |
A+,
AB+ |
A+ |
A+, A-, O+, O- |
| A- |
A-
A+, A-,AB+, AB- |
A- |
A-, O- |
| B+ |
B+,
AB+ |
B+ |
B+, B-, O+, O- |
| B- |
B-
B+, B-, AB+, AB- |
B- |
B-, O- |
| O+ |
A+, B+, AB+, 0+ |
O+ |
O+, O- |
| O- |
A+, A-, B+, B-, AB+,
AB-, O+, O- |
O- |
O- |
| AB+ |
AB+ |
AB+ |
A+, A-, B+, B-,AB+, AB-, O+, O- |
| AB- |
AB+, AB- |
AB- |
A+, B-, AB-, O- |
Blood
Inheritive
Patient 1, Patient 2, possible blood
group. |
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How
Are Blood Groups Inherited?
Blood groups for each individual are determined
by genes which are inherited from both
parents. Genes for the Rh negative and
O groups from one parent are masked by
the presence of Rh positive and A or B
genes from the other parent. Thus people
who are apparently A or B Rh positive
may also carry genes for the O and Rh
negative blood groups which can be inherited
by their children.
Are There Any Other Blood Groups?
There are 15 other blood group systems
- in all almost 400 antigens have been
discovered. However, most of these do
not normally require matching for transfusion
purposes. |
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