Blood Samples
You can be certain that during a stay in a hospital you will receive visits from the laboratory technician who will take a sample of blood. You will notice that the technician who draws your blood will collect it in glass tubes with rubber stoppers of different colors. For a complete blood count (CBC), the stopper is usually a mauve color because there is a chemical in the tube which stops the blood from clotting. For many other tests, the stopper is red and the tube is plain glass. The blood is allowed to clot and the clear yellowish fluid known as serum is used for testing. With modern needles and experienced personnel, the discomfort of having your blood taken is minimal.
Complete Blood Count
When a CBC is done, the technicians calculate the number of red blood cells per cubic milliliter of blood. They also look at the size and shape of the cells, the proportion of red cells to the total amount of blood 9the hematocrit), and the amount of hemoglobin (protein in the red cells that carries oxygen to the tissues) in the samples. A low red blood cell count is called anemia. If you are anemic, your body cells may not receive an adequate supply of oxygen. Common causes of anemia are loss of blood or lack of iron in the diet, but it may also be caused by a malfunction of the bone marrow that produces the cells or an increased rate of destruction of the red cells. These normally survive for about four months before being broken down.
The technicians also look at the white cells. Although there is only one variety of red blood cells, there are several different types of white blood cells. They are one of the main body defenses against infection and disease. An increase in the number of normal white cells is often seen if the body is fighting an infection such as appendicitis or pneumonia. Although a normal white blood count (WBC) would not exclude the condition, it would make it less likely. An excessive number of abnormal white cells may indicate leukemia.
