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Blood donation is everyone’s fallback in emergencies and life threatening sickness. The need for blood donors can never be trumpeted enough, without enough of blood supply in each type there are complications. This article is a look into a factor that every transfusion procedure depends on: blood type compatibility.
Hypothetical problem: you figured in a road accident, you’ve lost much blood and when you reached the hospital, there is no compatible blood to give you.
Solution: wait for a compatible donor.
Most asked question: Isn’t all blood the same?!
Some people may not realize this, but blood compatibility is a very important aspect to consider in blood transfusion. A type “B” leukemia patient cannot receive blood from a type “A” blood donor. The same can be said for a trauma victim with “O” blood type. He cannot receive blood from a donor type “A”.
Going back to the question we have above, the answer to that is: NO. People have different blood types, there are four types of blood according to the ABO blood group system: A, B, AB and O.
The differences in human blood are caused by the presence or absence of antigens and antibodies. The antigens are found on the surface of the red blood cells while the antibodies are in the plasma. Each blood group has different types and combinations of antigens and antibodies which explains why blood compatibility is vital for every blood transfusion. Incompatible blood that mixes with patient’s blood is a dangerous thing for reasons which we will dive into in the latter part of this article.
To understand which is compatible to which, take a look at the chart below:
People with blood type A have the A antigen and the plasma in their blood can fight against type B blood. This means they can receive blood from types O and A, but not from types B or AB.
People with B blood type have B antigen and antibodies to type A blood. They can receive blood from types O and B, but not from types A or AB.
People with AB blood type have A and B antigens and no antibodies. They can receive blood from types A, B, AB and O.
People with O blood type have no antigens and have antibodies to both A and B blood, making this type not compatible for types A, B and AB. They can only receive blood from type O blood but they can donate to all blood types. People who are type O are considered as the universal donor while type AB’s are the universal recipient.
Your blood type depends greatly on heredity. This is why many blood transfusions are between the recipient and an offspring, the parents, siblings or other close family members. Every blood donor should know that a blood donation can save people, most especially those who share familial ties.
What happens if non-compatible blood types are mixed?
Before the 1900s, people experimented with blood transfusions but many patients had died because of incompatible blood type. It was in 1901 when Karl Landsteiner, an Austrian biologist and physician, discovered the human blood groups. Since then, blood transfusions had become effective and safer for patients.
Even today, there are still instances of mismatched blood transfusions. When someone is given an incompatible blood type, this can result in terrible side effects. One of the serious problems that happen is Acute Hemolytic Transfusion Reaction.
Acute Hemolytic Transfusion Reaction occurs when the donor’s red blood cells are destroyed by the antibodies as it mixes with the patient’s blood circulation. Acute Hemolytic Transfusion Reaction (AHTR) is considered a medical emergency because it leads to rapid destruction of the donor’s red blood cells by the host antibodies. It may also occur when the patient’s red blood cell antigens are attacked by the antibodies from the donor’s plasma. This reaction is more severe when a type O patient is infused with a type A blood.
Why does this happen?
Acute Hemolytic Transfusion Reaction is unintentional. Most of hemolytic reactions are caused by human error: either by transfusing of improperly labeled blood to the wrong patient or by inaccurate identification of pre-transfusion blood samples. If a patient experiences any of the symptoms mentioned above, quickly notify the hospital blood bank in order for them to double check the transfusions of other patients.
Aside from the ABO blood group system, which we have discussed in the first paragraphs, there is another blood group system that is checked when blood typing is done. The Rhesus (Rh) factor is the blood group checked after verifying the ABO type. Rh factor is an antigen (protein or polysaccharides) that exists on the surface of red blood cells in most people. Rh blood group has 50 defined-group antigens and Rh factor (Rh-negative and Rh-positive) refers to the absence or presence of one of the proteins- the D antigen.
More than 85% of people in the world are Rh-positive. Those who have Rh factor in their blood are considered to have positive (+) blood type while those who don’t have Rh factor are called to have negative (-) blood type. They are written this way: A+ or B+ and A- or B-.
Rh- blood type people get the short end of the stick because there is no other blood type except an RH- kind can be accepted by their bodies. In the chart above, Recipient and Donor blood type compatibility can be seen as checks wile incompatibility are symbolized as x’s.
For example, if you have Rh-positive blood, you can receive either Rh-positive or Rh-negative red blood cell transfusions. However, if you have Rh-negative blood, you can only receive Rh-negative red blood cells except in dire emergencies with the authorization of a doctor.
This is the last testing of blood type in supply before approval for transfusion. Blood contains antigens that are not present in other people’s blood, whether the patient’s blood type isn’t available or even a full match for RH and ABO is exact. Cross matching is done to make sure that the donor’s red blood cells will match against the recipient’s serum. To do this, a little amount of the recipient’s serum is mixed with a small amount of the donor’s red blood cells. The combination is examined under a microscope and if the donor’s red blood cells are agglutinated by the antibodies in the receiver’s serum, then their blood is incompatible. Agglutination is when blood clumps up and clogs the veins and then explodes spreading toxins in the recipient’s blood. If they are not agglutinated, then it means their blood is compatible and the transfusion can be done.
Blood Incompatibility between Mother and Baby
Blood type incompatibility is not only applicable during blood transfusions; this also happens during pregnancy. One common type of incompatibility among pregnant women is the RH incompatibility. This happens when a mother’s blood type conflicts with her baby’s.
- The mother is Type O and the baby is Type A, B or AB.
- The mother is Type A and the baby is either Type B or AB.
- The mother is Type B and the baby is Type A or AB.
The mother’s blood cells could develop antibodies that can attack the baby’s blood cells and cause jaundice when the former’s RBCs cross into the placenta or fetus during pregnancy.
Rh incompatibility also happens when the mother is Rh-negative while the baby is Rh-positive. The mother’s body will create an auto-immune response that attacks the fetus’ blood cells and treat it as if it were a bacterial or viral invader. This immune response is slow to thrive in first pregnancies but the risk is higher for subsequent pregnancies with an Rh incompatibility.
Rh incompatibility used to be a serious problem, but thanks to medical advances, this can be prevented and treated now.
If an Rh incompatibility is diagnosed in the mother, doctors administer a series of two Rh immune-globulin shots during the first pregnancy. The first shot is administered about 28 weeks into the pregnancy while the second is given within 72 hours after giving birth. Rh immune-globulin performs like a vaccine that prevents the mother’s body from making any potentially harmful Rh antibodies that can cause serious complications in the baby or complicate any future pregnancies by the mother.
Once a mother is determined to have developed Rh antibodies, the pregnancy will be monitored carefully to ensure that the levels are not too high. But there are also instances when the incompatibility is severe and the baby is in danger. In this case, a series of blood transfusions, also called exchange transfusions, can be done either while the baby is still in the uterus or after delivery.
Blood donation is an easy process, transfusion on the other hand is a tedious process that involves the 3 compatibility tests mentioned in this article. Medical personnel must really be careful in examining one’s blood type because a wrong transfusion can be the death of the recipient.
Blood compatibility is a standard process for transfusion, yet without enough blood in stock finding the best match may be difficult when blood supply is low. If you are a type O, make it a life long service to donate blood to hospital centers. Your blood is a universal blood type, please take time to go to blood donation centers near your place and give blood.
The need for blood is a reality every day, the world needs a pint of blood to add life to everyone who needs it.
Help eliminate the blood shortage, Join the International Blood Registry.