CBC

Meaning of CBC: A CBC is often the first laboratory test ordered when evaluating unexplained fatigue, infection, bleeding, or bruising.

Definition of CBC

CBC stands for complete blood count, a common blood test that measures the number and characteristics of red blood cells, white blood cells, and platelets circulating in a blood sample. It is among the most frequently ordered laboratory tests, used both to evaluate specific symptoms and as part of routine health screening.

A CBC reports several distinct measurements, including the total count of each cell type, the concentration of hemoglobin, the protein within red blood cells that carries oxygen, and details about red blood cell size, along with a breakdown of the different types of white blood cells present.

Because red blood cells, white blood cells, and platelets each serve different functions, an abnormal CBC result can point toward a wide range of underlying conditions, from a common infection or nutritional deficiency to a bleeding disorder or a blood cancer, and the specific pattern of abnormality generally guides what further testing is needed.