Hemoglobin volume is usually the amount of hemoglobin per liter of blood. 1. Hemoglobin is the special protein that transports oxygen within red blood cells, the protein that gives blood its red color, and consists of globulin and hemoglobin. The reference value is based on the number of grams of hemoglobin per liter of blood, which varies slightly according to gender and age: 120g～160g/L for adult males; 110g～150g/L for adult females; 180g～190g/L for newborns; and 120g～140g/L for children. 2. The elevation or decrease of hemoglobin can refer to the clinical significance of the elevation or decrease of red blood cells. Newborns and highlanders may have physiologic increases in hemoglobin. Pathological increase can be seen in true erythrocytosis, congenital heart disease and other diseases. Decrease can be seen in various anemia such as aplastic anemia, massive blood loss such as gastrointestinal bleeding and leukemia and other diseases.