Complete Blood Count

A complete blood count (CBC) provides important information about the kinds and numbers of cells in the blood: red blood cells, white blood cells and platelets. A CBC can help you and your health professional evaluate symptoms (such as weakness, fatigue, or bruising, state of hydration and dehydration) and diagnose conditions (such as anemia, leukemia, infection, and many other disorders) and to monitor treatment effects with some high risk drugs, etc.

Red blood cells carry oxygen from the lungs to the rest of the body. They also help carry carbon dioxide back to the lungs so it can be exhaled. The red blood cell count shows the number of red blood cells in a sample of blood. If the RBC count is low, the body may not be getting the oxygen it needs. If the count is too high (a condition called polycythemia), there is a risk that the red blood cells will clump together and block tiny blood vessels (capillaries).

This test measures the amount of space (volume) red blood cells occupy in the blood. The value is given as a percentage of red blood cells in a volume of blood. For example, a hematocrit of 38 means that 38% of the blood's volume is composed of red cells.

Hemoglobin is the substance in a red blood cell that carries oxygen. The hemoglobin test measures the amount of hemoglobin in blood and is a good indication of the blood's ability to carry oxygen throughout the body.

White blood cells protect the body against infection. If an infection develops, white blood cells attack and destroy the bacteria, virus, or other organism causing it. White blood cells are bigger than red blood cells and normally fewer in number. When a person has a bacterial infection, the number of white cells can increase dramatically. The white blood cell count shows the number of white blood cells in a sample of blood. The number of white blood cells is sometimes used to identify an infection or monitor the body's response to cancer treatment.

Platelets (thrombocytes) are the smallest type of blood cell. They play a major role in blood clotting. When bleeding occurs, the platelets swell, clump together, and form a sticky plug that helps stop the bleeding. If there are too few platelets, uncontrolled bleeding may be a problem. If there are too many platelets, there is a risk of a blood clot forming in a blood vessel.

In this test, a drop of blood is spread (smeared) on a slide and stained with a special dye. The slide is then examined under a microscope. The numbers, size, and shape of red blood cells, white blood cells, and platelets are recorded. Blood cells with unusual shapes or sizes can help diagnose many blood diseases, such as leukemia, malaria, or sikle cells anemia.

There are five major kinds of white blood cells:
neutrophils, lymphocytes, monocytes, eosinophils, and basophils.

Immature neutrophils, called band neutrophils, are also included and counted as part of this test.

Each type of cell plays a different role in protecting the body. The numbers of each one of these types of white blood cells give important information about the immune system. An increase or decrease in the numbers of the different types of white blood cells can help identify infection, an allergic or toxic reaction to certain medications or chemicals, and many conditions (such as leukemia ).

Neutrophils

Granular leukocyte (white blood cell). Neutrophils are phagocytes engulfing bacteria and cellular debris. An increase in the number of neutrophils occurs in acute infections, certain malignant neoplastic diseases, and some other disorders.
Lymphocytes
Agranulocytic leukocyte (white blood cell) that normally makes up about 25% of the total white blood cell count but increases in the presence of infection. Lymphocytes occur in two forms: B cells, the chief agents of the humoral immune system, which recognize specific antigens and produce antibodies against them; and T cells, the agents of the cell-mediated immune system, which secrete immunologically active compounds and assist B cells in their function.
Monocytes

Type of granular leukocyte (white blood cell) that functions in the ingestion of bacteria and other foreign particles.
Eosinophils

White blood cell readily stained with eosin. Eosinophils, normally about 1-3% of the total white blood cell count, are believed to function in allergic responses and in resisting some infections.
Basophils

Type of white blood cell (leukocyte), with coarse granules that stain blue when exposed to a basic dye. Basophils normally constitute 1% or less of the total white blood cell count but may increase or decrease in certain diseases.
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Blood should be drawn fasting in the morning and before you take iron or a blood transfusion. Iron determinations on patients who have had blood transfusions should be delayed for at least 4 days.
Serum iron level measures the level of iron in the liquid part of your blood. It also measures the amount of Transferrin, a blood protein that transports iron from the gut to the cells that use it. Your body makes Transferrin in relationship to your need for iron.
When iron stores are low, Transferrin levels increase, while Transferrin is low when there is too much iron.
Usually about one third of the Transferrin is being used to transport iron. Because of this, your blood serum has considerable extra iron-binding capacity, which is the Unsaturated Iron Biding Capacity (UIBC). The TIBC equals UIBC plus the serum iron measurement. Some laboratories measure UIBC, some measure TIBC, and some measure transferrin.