800CC is 800ml of blood, because CC means ml, and in clinical practice, the number of milliliters is mostly used to indicate the volume of blood. 800ml of blood accounts for about 1/6 of a normal person’s own blood volume. In clinical practice, if a person loses 800ml of blood at one time, the patient will show obvious symptoms of hemorrhagic anemia, manifested as pallor, dizziness and weakness. In serious cases, a series of symptoms such as panic and shortness of breath may appear, and in more serious cases, symptoms of hemorrhagic shock such as cold extremities and decreased blood pressure may also appear. Therefore, in clinical practice, the amount of blood loss can be roughly inferred from the patient’s symptoms of anemia. In clinical transfusion, we can also project the degree of hemoglobin elevation after transfusion according to the transfusion volume. When 800ml of blood is input, the general hemoglobin can be elevated by about 12-15g/L.