Complete Blood Count

Complete blood count reveals a lot about your health

There are three main categories of cells in human blood: red blood cells (RBCs), white blood cells (WBCs) and platelets. Red blood cells carry oxygen to the body tissues. Hemoglobin is a protein in the red blood cells that is responsible for oxygen "transportation." White blood cells play a vital role in immunity—the body's ability to fight off illness. There are several different types of white blood cells, each having different functions related to immunity. Platelets help the blood to clot.

A complete blood count (also called CBC, CBC with differential, or blood count) is a count of the red blood cells, white blood cells, and platelets in a definite volume of blood. A CBC also includes a measurement of hemoglobin, the protein that carries oxygen within the red blood cells. A hematocrit is a measurement of the percent volume of red cells, white cells, and plasma. A differential WBC count is a count of the different types of white blood cells.

A CBC can tell your doctor a great deal about the state of your health. Medical conditions that cause an abnormal blood count include anemia, the presence of an infection and some kinds of cancer. Blood counts can be used for screening, diagnosis or management of certain diseases and medical conditions.