A laboratory evaluation of all the cells that circulate in the blood, including the number and the hemoglobin content of red blood cells, the white blood cells (and their subtypes), and platelets. The typical CBC provides assessments of size and shape of red blood cells and platelets as well.
The CBC is among the most common blood tests performed in the clinical laboratory and aids in the diagnosis of anemia and erythrocytosis; bleeding and the repletion of blood cells by transfusion, thrombocytopenia and thrombocytosis; and infections and leukemias. Blood is obtained for the test from venipuncture or aspiration from an indwelling vascular access or port. It is taken to the laboratory in a tube that contains the anticoagulant ethylenediaminetetraacetic acid (EDTA).