Garry Blaser, age 11, of Enid, Oklahoma, for his question:
Does a person's blood type change?
A person's blood is a complicated brew of assorted chemicals. In a healthy body the ingredients are rich and chemically balanced. Sickness causes many unhappy changes in a person's blood and the balanced recipe may lose some of its peppy bounce with age. But, so far as we know, a person's basic blood type does not change throughout life.
A person's blood group is a very important item in his medical history. In cases of surgery or serious accident, a patient may need a transfusion of blood from someone else to restore him to life. Bottles of red blood are donated and kept on hand for these emer¬gencies. They are carefully labeled according to their blood groups, because a patient can accept only blood of a certain type. Whole blood from a donor must be the right type to mix with the blood of the patient. A transfusion of the wrong type causes the patient's blood to clot and the clumps could be fatal.
Nowadays, certain types of transfusions can be done which do not depend on matching blood types. This is not because medical science has learned how to change blood types. The assorted chemicals in a person's blood may change for the better or for the worse. But his basic blood type does not change. It is a very general classification based on merely one or two of the hundreds of assorted chemicals in the complicated blood stream.
At the turn of the century, the new idea of blood transfusions was full of promises. Patients suffering from serious surgery .:were revived. Lives were saved after serious acci¬dents. But with all this success, there were many miserable failures. Doctors could not understand why transfusions of whole blood were fatal to certain patients and lifesavers to others. So research scientists analyzed blood samples from different people more close¬ly. Not all blood, they discovered, is alike. Some types refuse to blend with others. When these types are mixed, the floating red cells clump together and the lumpy clots tend to clog vessels in the patient's circulatory system.
The clumping of red cells is called "agglutinating,." The problem occurs when certain agglutinogen substances in the red cells are mixed with certain agglutin proteins in the liquid plasma. A sample of your blood reveals a compatible blend of these substances. This is true for everyone. But the blended recipes are not all alike. Certain agglutinogens in the person's red cells may be forced to cause clumping by certain agglutinins in somebody else's plasma.
The agglutinating factors were classed as type A and type B. Your blood may contain either of these factors, both of them or none at all. You belong in group A or B, in group AB or 0 and there you stay. An 0 type can give whole blood to anyone. An AB type can accept blood from anyone. Other mixtures may be disastrous. It is simple and sensible to have your blood type on record in case of emergency.
The red cells that contain the agglutinating factors float in the liquid plasma of the blood. For some types of transfusions, this plasma is the vital ingredient. Nowadays, in many cases, the red cells can be removed and with them goes the clumping problem. A person's blood type does not change. But medical science has changed the picture of transfusions between blood groups for the better. With the red cells removed, anyone's plasma may be acceptable to all four groups.