The following should seem quite obvious: Every human needs blood in order to survive. This complex tissue is a necessary element that travels through the body and carries out many different functions. In some people, molecules of antigens known as agglutinogens are attached to red blood cells. Of these agglutinogens, there are two types with different properties: Type A and Type B. Conversely, there is a third type known as O in others that will have no such attached molecules. When classifying one’s blood by the presence or absence of these molecules, a system known as ABO is used to classify a person’s blood into one of four different types: A, B, AB, or O.
Furthermore, within each person’s blood, a protein known as Rh will either be present or not. If this protein is found to be present in the blood, the person’s blood type is said to be Rh-positive. If the opposite occurs and no Rh protein is found, the person’s blood type is conversely labeled as Rh-negative.
When referring to the agglutinogens that are typed A or B, these are produced by different enzymes. In turn, the enzymes are encoded by different versions of the same gene. From the time a new fetus is conceived, he or she will inherit two copies of a gene. One will come from the mother and the other from the father. The blood types that parents carry will determine that of their offspring. So what happens when the parents each have different blood types?
In simplest terms, it will depend on how the mother’s and father’s blood types are combined. It stands to reason that if both parents happen to have the same blood type, then so will their child. Of course, this isn’t always going to be the case. For example, if one parent has Type A and the other has Type O, the child will have Type A. Similarly, if one parent has Type B and the other has Type O, the child will have Type B. In the case of one parent with Type A and the other with Type B, the child will have Type AB.
Different mixtures of parental Rh factors will likewise determine whether their children will or will not carry this protein in their bloodstream.
In instances when a person needs a blood transfusion, it becomes of utmost importance to ensure that the donor’s and recipient’s blood types will match. If they don’t, the antibodies in the recipient’s fresh supply of blood that aid in fighting infection will treat this donated blood as a foreign invader. When this happens, it results in an immune response that clots the blood.
Needless to say, this would not produce a positive outcome for the poor individual receiving the transfusion. In fact, if such an error wasn’t detected in time, it could kill them! Before these different types were discovered during 1900 and 1901 by Karl Landsteiner at the University of Vienna, this is precisely what happened to many unfortunate recipients of blood transfusions.
However, there are two types of blood that can universally be donated, and they are Type O and Type AB. As stated earlier, people with Type O have no attached molecules, and thus the recipient won’t have to worry about having an immune response. People with Type AB can also donate to anybody because there would be no antibodies to recognize Type A or B molecules.
There are some people out there that don’t know what type of blood they have. In such instances, it is advisable to obtain this information. While some birth certificates will list it, medical personnel can also take a sample and clear up the mystery almost immediately.
