| Suppose you lost a lot of blood, what
would a doctor do? Replace the blood as quickly as possible by giving you a
transfusion of blood donated by another person. But the doctor can't use just
anyone's blood. The donor's blood has to be of a type that won't be destroyed by
your blood. Blood type? What's that? To find your blood type, the doctor sends your blood to a laboratory. There your red cells are separated from the other parts of your blood. These ceils may have certain antigens (special proteins) on their surfaces—"A" antigens and/or "B" antigens. If your red ceils have "A" antigens you are Type A; "B" antigens make you Type B; both "A" and "B" make you Type AB; neither "A" nor "B' antigens makes you Type O. How do you find these antigens? A lab technician mixes your red blood cells with two kinds of blood serum. One contains anti-A antibodies. The other kind contains anti-B antibodies. An antibody is a substance that "attacks" a particular antigen, in this case "A" or "B" antigens. The technician then looks at each mixture under a microscope to see what will happen to your red blood cells. Certain mixtures may make your red cells clump together. By finding which mixtures do this and which do not, the technician can figure out your blood type. But blood typing isn't the only reason to have a blood test taken. It can also check for signs of infection. How? When you have an infection, especially a serious one, the number of white blood cells soars. This is normal response of your body to an invasion of germs. This time a sample of blood goes to the lab for a CBC — complete blood count. A technician will examine your blood under a microscope — counting the white cells in a small marked-off area If the number is much higher than it ought to be, the doctor may need to treat you to be sure the infection doesn't spread. Other blood tests can determine the concentration of various chemicals in your blood or the variety and types of blood cells circulating in the blood. The information hidden in a drop of blood may lead a doctor to suggest ways to treat, or avoid dangerous health conditions. Was the stick in the finger or arm necessary? If protecting yourself from danger is necessary, the answer has got to be... yes! |