A complete blood count (CBC) is a blood test used to evaluate your overall health and detect a wide range of disorders, including anemia, infection and leukemia.
A complete blood count test measures several components and features of your blood, including:
Red blood cells, which carry oxygen
White blood cells, which fight infection
Hemoglobin, the oxygen-carrying protein in red blood cells
Hematocrit, the proportion of red blood cells to the fluid component, or plasma, in your blood
Platelets, which help with blood clotting
Abnormal increases or decreases in cell counts as revealed in a complete blood count may indicate that you have an underlying medical condition that calls for further evaluation.