NCI Dictionary of Cancer Terms

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full blood count
(… blud kownt)
A measure of the number of red blood cells, white blood cells, and platelets in the blood. The amount of hemoglobin (substance in the blood that carries oxygen) and the hematocrit (the amount of whole blood that is made up of red blood cells) are also measured. A full blood count is used to help diagnose and monitor many conditions. Also called blood cell count, CBC, and complete blood count.

EnlargeComplete blood count (CBC); left panel shows blood being drawn from a vein on the inside of the elbow using a tube attached to a syringe; right panel shows a laboratory test tube with blood cells separated into layers: plasma, white blood cells, platelets, and red blood cells.

Complete blood count (CBC). Blood is collected by inserting a needle into a vein and allowing the blood to flow into a tube. The blood sample is sent to the laboratory and the red blood cells, white blood cells, and platelets are counted. The CBC is used to test for, diagnose, and monitor many different conditions.