Complete Blood Count

The Complete Blood Count (CBC) remains one of the most common blood tests performed today. It consists of a combination of tests which analyze the cellular make up of the blood. Some specific analyses of the CBC are as follows:

The hematocrit represents the percentage of the blood volume which consists of red blood cells. For example, an hematocrit of 25% means that there are 25 milliliters of red blood cells in 100 milliliters of blood. The red cells make up a quarter of the blood.

The normal range of the hematocrit is dependent of the age of the individual. A low hematocrit is a sign of anemia. Such anemia may be from nutritional factors, blood loss , or other disease processes.

Hemoglobin is the protein molecule within red blood cells that carries oxygen and gives blood its red color. Iron is important in the chemical structure of hemoglobin. A low hemoglobin represents anemia. Higher than normal hemoglobin levels can be seen in people living at high altitudes and in smokers

White blood cells are a normal component of blood. Their primary function is as a defense against infections. An elevated white blood cell count may be a sign of infection. Some viral infections may lower the white blood count. The are 5 different types of white blood cells. Increases or decreases in these cells may indicate particular medical conditions.

Blood platelets are a component of blood which are important in blood clotting (to stop bleeding). Platelets act by sticking to each other and clotting the bleeding site. Aspirin affects the clotting of blood by decreasing the effectiveness of platelets.

There are other tests which comprise the CBC. Explanations are beyond the scope of this website.