A QUICK REVIEW AT BLOOD TYPING AND WHY IT IS IMPORTANT TO KNOW YOUR BLOOD GROUP
It is surprising how most people disappoint me or feel disappointed themselves altogether when I ask them what their blood group is and they do not know. This is because, most people live to adulthood without caring to find out their blood groups, and not because they need to donate blood or are in need of blood transfusion, but I really think it is important that you know your blood group, as a general rule like you know your name. How useful is it to know my blood type? What can it tell me about myself? It can be helpful to know your blood type for a number of reasons. Let’s review how your blood type is determined to understand why it’s important and how it can affect your health. The importance of knowing your blood type is to prevent the risk of you receiving an incompatible blood type at a time of need, such as during a blood transfusion or during surgery. If two different blood types are mixed, it can lead to a clumping of blood cells that can be potentially fatal. Thankfully, prior to doing a blood transfusion, your blood type is tested and cross-matched against the donor blood, which minimizes the risk of transfusion reaction. Blood typing is a test that determines a person’s blood type. Austrian Karl Landsteiner discovered blood types in 1901. Before that, blood transfusions were risky and potentially lethal. Landsteiner made the process much safer, and he was awarded the Nobel Prize for his work.
Blood typing is especially important for pregnant women. If the mother is Rh-negative and the father is Rh-positive, the child will likely be Rh-positive. In these cases, the mother needs to receive a drug called RhoGAM. This drug will keep her body from forming antibodies that may attack the baby’s blood cells if their blood becomes mixed, which often happens during pregnancy.
What are the different types of Blood?
Your blood type is determined by what kind of antigens your red blood cells have on the surface. Antigens are substances that help your body differentiate between its own cells and foreign, potentially dangerous ones. If your body thinks a cell is foreign, it will set out to destroy it.
The ABO blood typing system groups your blood into one of four categories:
- Type A has the A antigen.
- Type B has the B antigen.
- Type AB has both A and B antigens.
- Type O has neither A nor B antigens.
If blood with antigens that you don’t have enters your system, your body will create antibodies against it. However, some people can still safely receive blood that isn’t their blood type. As long as the blood they receive doesn’t have any antigens that mark it as foreign, their bodies won’t attack it.
In other words, donations work as follows:
- O: Type O individuals can donate blood to anyone, because their blood has no antigens. However, they can only receive blood from other type O individuals (because blood with any antigens is seen as foreign).
- A: Type A individuals can donate to other type A individuals and type AB individuals. Type A individuals can receive blood only from other type A individuals and type O individuals.
- B: Type B individuals can donate blood to other B individuals and AB individuals. Type B individuals can receive blood only from type B individuals and type O individuals.
- AB: Type AB individuals can give blood only to other AB individuals, but can receive blood of any type.
Blood types are further organized by Rh factor:
Rh-positive: People with Rh-positive blood have Rh antigens on the surface of their red blood cells. People with Rh-positive blood can receive Rh-positive or Rh-negative blood.
Rh-negative: People with Rh-negative blood do not have Rh antigens. People with Rh-negative blood can receive only blood that is also Rh-negative.
Together, the ABO and Rh grouping systems yield your complete blood type. There are eight possible types: O-positive, O-negative, A-positive, A-negative, B-positive, B-negative, AB-positive, and AB-negative. While type O-negative has long been considered a universal donor, more recent research suggests that additional antibodies are sometimes present and may cause serious reactions during a transfusion.
What does your blood type say about your health?
Most of the time, the purpose of blood typing is to know who you can safely donate blood to or receive blood from. But your blood type may also put you at risk for certain medical conditions. Here are three ways your blood type and your health may be connected.
Are there any risks for blood typing?
You will need to have your blood drawn in order to have it typed. Having your blood drawn carries very minimal risks, including:
- Bleeding under the skin (hematoma).
- Fainting or feeling lightheaded.
- Infection at the puncture site.
- Excessive bleeding.
Preparing a blood typing Assay
The blood draw can be performed at a hospital or a clinical laboratory. Your skin will be cleaned before the test with an antiseptic to help prevent infection. A nurse or technician will wrap a band around your arm to make your veins more visible. They will use a needle to draw several samples of blood from your arm or hand. After the draw, gauze and a bandage will be placed over the puncture site.
In order to determine your blood type, a lab technician will mix your blood sample with antibodies that attack types A and B blood to see how it reacts. If your blood cells clump together when mixed with antibodies against type A blood, for example, you have type B blood. Your blood sample will then be mixed with an anti-Rh serum. If your blood cells clump together in response to the anti-Rh serum, it means that you have Rh-positive blood.
Blood group reagents are solutions that are used to determine blood groups. The reagents contain antibodies that will detect the presence of the appropriate antigens on the surface of red blood cells.
The reagents can cause the agglutination (clumping) on the test red blood cells which carry the appropriate antigen. No clumping of the test red blood cells indicates the absence of the appropriate antigen.
There are several techniques that can be used to detect blood groups. All techniques are based on the binding of an antibody to the appropriate antigen which is called agglutination. The agglutination can be seen macroscopically as the clumping together of the red cells.
- The Direct Antiglobulin Technique (DAT) involves washing the test cells in a saline solution in a test tube. After the washing of the red cells, the saline solution is removed from the test tube and a bridging reagent (Anti-Human Globulin reagent) is added to the red cells in the test tube. The test tube is spun in a centrifuge. The test result (agglutination or no agglutination) is read macroscopically.
- The Indirect Antiglobulin Technique (NISS IAT) requires the red cells to be mixed in a test tube with a blood grouping reagent. The test tube (containing the blood grouping reagent and the red cells) is incubated at 37 °C for 15 minutes. After incubation, the red cells are washed with a saline solution. After washing the red cells, the saline solution is removed from the test tube and a bridging reagent (Anti-Human Globulin reagent) is added to the red cells in the test tube. The test tube is spun in a centrifuge. The test result (agglutination or no agglutination) is read macroscopically
Your blood type can be determined in a matter of minutes. Once you know your blood type, you can donate blood and receive transfusions from donors in the compatible blood groups. If you haven’t had your blood group determined, make an effort today.
As always, stay well and healthy.