The O’s and A’s of blood compatibility

Fast Facts

• South Africa uses in excess of 1 million units of blood every year

• One person may need several litres of blood in the case of a serious injury or surgery

• The average person has about 5 litres of blood in their body

• You donate 500ml with every blood donation

• 1 unit of blood can save up to 3 lives

• You can donate blood every 56 days


Who can receive which blood groups

As you can see above, O blood group is the most sought after blood type because it can be given to anyone. AB group, while very rare, can receive any blood type.


A note about Rhesus

You have probably heard about blood being Rhesus positive or Rhesus negative. People whose blood is Rhesus positive have a substance known as D antigen on the surface of their red blood cells while those without the antigen are called Rhesus negative. Rhesus negative persons can only receive Rhesus negative blood, while Rhesus positive people can receive both.


Why do I pay for blood when it is donated for free?

Blood donors in South Africa do not get any financial rewards for their blood donation, however there is a cost involved when you receive blood. This is because of the costs involved in collection of the blood (the staff, blood bags etc.), testing the blood for blood type and diseases in the blood bank laboratories, and the additional blood matching done before the blood can be transfused to make sure the patient’s blood is completely compatible with the donated blood.


To find out more about how you can become a blood donor, click here.