A complete blood count (CBC) is a blood test that reports the levels of three different types of blood components: red blood cells, white blood cells and platelets. The red blood cells (RBCs) are the cells responsible for the transport of oxygen from the lungs to the various tissues in the body. If the total number of the RBCs is low, a diagnosis of anemia
may be made. This can be due to a variety of causes, including chronic blood loss from the gastrointestinal tract, Vitamin B12 deficiency, and chronic kidney disease
, to name a few. The CBC will also report different numbers about the size of the RBCs and the amount of hemoglobin (the part of the cell that carries oxygen) in each cell which can help determine the cause of any anemia.
The number of WBCs may be high in cases of inflammation or infection, or more rarely, types of cancer such as leukemia. The WBC count may be very low sometimes due to bone marrow disorders. Platelets are the cells that aid in the cessation of bleeding
. Similarly, platelets may be low due to bone marrow disorders, or due to an enlarged spleen (often seen in advanced liver disease). Platelets may be elevated in the setting of inflammation.