Hemoglobin is composed of iron and protein found in red blood cells. It carries oxygen to all the cells in the body. Low hemoglobin can indicate anemia, or iron deficiency, caused by vitamin deficiencies and malnutrition.
Hematocrits measure red cell volume.
Low results are another indication of anemia. White blood cells are infection fighters. Elevated white blood counts may be caused by viral or bacterial infections. Trauma to the body or diseases may increase or decrease the white blood cell count. Red blood cell count can indicate whether the body is producing enough red cells which transport oxygen to body cells.