Carbon dioxide in renal function test generally refers to carbon dioxide binding capacity, the normal range is 22-29mmol/L, different hospitals test standards are slightly different. 30.6mmol/L belongs to the mildly elevated, which may be caused by high carbon dioxide, metabolic alkalosis, etc. 1.High carbon dioxide: It means the body’s ventilation capacity is reduced and there is carbon dioxide retention. 1. High carbon dioxide: This means that the body’s ability to ventilate is reduced and there is carbon dioxide retention. Carbon dioxide mainly represents the body’s ability to ventilate. It is usually caused by obstruction of foreign bodies in the airway and asthma attacks. In addition, causes such as pleural effusion can also lead to a rise in carbon dioxide. 2. Metabolic alkalosis: A disorder of acid-base balance caused by excessive loss of acid from the body through the gastrointestinal tract and the kidneys, or by excess alkali entering the body from outside the body, resulting in elevated primary plasma HCO3- and pH. When the patient’s renal function test carbon dioxide binding capacity is high, it is recommended that the patient should go to the hospital for relevant examination and treatment, and follow the doctor’s instructions as soon as possible, so as not to be negligent, so as not to delay the condition.