Low residual alkalinity in whole blood, which should be low residual alkalinity, indicates that the body’s alkalinity reserve is significantly reduced, and the body’s alkalinity storage is insufficient, i.e., metabolic acidosis occurs. It may be caused by excessive production of acidic substances in the body, excessive loss of bicarbonate in the body, and obstacles to the discharge of acidic substances in the body. 1. Excessive production of acid in the body: ketoacidosis caused by severe trauma, crush injury, hypoxia, insulin deficiency, etc., as well as alcoholism, liver dysfunction, etc., will lead to acidosis, resulting in low residual alkalinity in the whole blood. 2. Excessive loss of bicarbonate in the body: patients with intestinal diseases, such as diarrhea, intestinal fistula, pancreatic fistula, etc., will lead to excessive loss of bicarbonate, resulting in patients with acidosis caused by low residual alkalinity in whole blood. 3. The acidic substances in the body are discharged by the obstacle: the kidney function is damaged, such as glomerular filtration rate decline, renal edema, renal failure, etc., will lead to a large number of acidic substances retained in the body, acidosis, resulting in low residual alkalinity of whole blood. When patients have metabolic acidosis resulting in low blood residual alkalinity, they should go to the hospital to clarify the relevant causes and strictly follow the doctor’s instructions for treatment.