Why is Blood grouping important?
A person’s blood type becomes a crucial matter when a blood transfusion is necessary. If an individual is transfused with the wrong blood type, a reaction that severely compromises the immune system can result. There are different levels at which a mismatched transfusion can occur, from minor to major incompatibility. Minor factors may lead to very minor problems, but a major incompatibility of blood type during a transfusion can be serious.
Blood type is so important during a transfusion that donors giving blood to a blood bank must meet certain requirements. A blood transfusion is closely monitored, often by a haematologist.
In pregnancy…
Blood tests will check your blood type, your Rh status, and an antibody screen. Your blood type needs to be checked so that a potential mix-up of bloods can be averted if there is a need for a transfusion. Rh negative women need to be identified in advance so that they can be considered as candidates for RhoGAM, an immunoglobulin that is given at 28 weeks of pregnancy and within 72 hours of delivery in order for the mother to keep from becoming Rh sensitized. Occasionally, RhoGAM is also given when there is a potential risk for fetal blood to mix with the mother’s blood, such as in a car accident or in amniocentesis.Why it’s important (RhoGAM): Giving this medication prevents the mother’s body from mounting an antibody response against an Rh positive baby in future pregnancies. An antibody screen detects antibodies, both Rh and less common types, that may occur in the fetus or newborn.
Why it’s important (antibody screen): Antibodies have the potential for causing blood disease in the fetus and newborn.
In the case of organ transplants, the tissue of the donor organ must match the recipient’s blood type. A mismatch can cause rejection, and therefore, without a positive match, the transplant will not be conducted. Individuals placed on a transplant waiting list have their blood type thoroughly tested before being placed on the list.
What are the different blood groups?
In 1901, scientist Karl Landsteiner reported that blood could be classified into blood ‘types’.
There are 4 main blood groups A, B, AB and O, of which group O is the most common (47% of population). The blood type is determined by proteins called antigens found on the surface of red blood cells. If you have the antigen A on the red blood cells then you have got type A blood. When B antigen is present, you have type B blood, when both A and B are present, you have type AB blood. When neither are present you have type O blood.
Another blood group system involves Rhesus factors. The name Rhesus comes from the Rhesus monkeys in which the protein was first discovered. Rhesus factor D, the most important, is found in the blood of 85% of people, they are known as Rhesus positive. The remaining 15% are Rhesus negative. So people can be classified according to both systems, for example AB positive or O negative.
The Rhesus factor is important during pregnancy, a baby’s life can be endangered if it inherits a Rhesus positive blood type from its father while the mother is Rhesus negative. This is because the mother can form antibodies against the baby’s blood.
Here is a list of the blood types and their frequency in the general population :
| O Rh (D) Positive |
40% |
| O Rh (D) Negative |
7% |
| A Rh (D) Positive |
36% |
| A Rh (D) Negative |
6% |
| B Rh (D) Positive |
7% |
| B Rh (D) Negative |
1% |
| AB Rh (D) Positive |
2.5% |
| AB Rh (D) Negative |
0.5% |
Eldon card Blood grouping test procedure…
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Step 1
Place one drop of water in each field with a pipette. DO NOT LET THE WATER DRY. |
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Step 2 
Disinfect a finger. Let the finger dry. With a lancet make a small puncture.
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Step 3
Collect one drop of blood for each field on an ELDONstick®. Use a new ELDONstick® for each field. |
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Step 4
Blood drops should fit the base of the ELDONstick®.
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Step 5
Place the blood drops into the fields of your ELDONCARD®. Keep the stick in contact with the card. |
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Step 6
Mix blood and reagent with a rotating movement for approx. 15 seconds. Spread mixture to the perimeter of the circles.
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Step 7
Tilt the ELDONCARD® to a vertical position. After 10 seconds tilt the ELDONCARD® 180° to allow blood to travel across the reaction fields. Wait 10 seconds. Tilt the ELDONCARD® 90° to the left – wait 10 seconds. Tilt the ELDONCARD® 180° to the right – wait 10 seconds. Read and record the result. Let the ELDONCARD® dry (approx. 2 minutes if you use a hairdryer). |
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Step 8
Cover the agglutinations with adhesive foil to prevent deterioration of reactions and to seal possible infectious material.
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KAT Laboratory is a distributor of the eldon card system in Southern Africa
For more information on the Eldon Card Blood grouping please
Contact us on 0027 11 472 7300 or sales@katmedical.com
www.katmedical.com
