If it is an adult, the total carbon dioxide value of 30.5 is not serious; if it is a child, the total carbon dioxide value of 30.5 is on the high side. 1. Total carbon dioxide is the total serum carbon dioxide value, and the normal range for adults is 23-31mmol/L. The total serum carbon dioxide value of 30.5mmol/L is within the normal range. Since 30.5 is very close to the upper limit of 31mmol/L, you should pay more attention to observation in general, and go to the hospital in time once you have breathlessness, chest tightness and breathlessness. 2. Under normal circumstances, the total carbon dioxide value of children should be lower than 28mmol/L. If the total carbon dioxide value of children is 30.5mmol/L, it is at a higher level, and you should consult a doctor in time. A total carbon dioxide test result alone cannot determine whether there is a disease or not, when the test results come out, you should find a doctor in time to consult a doctor, the doctor based on all the results of the test to determine whether the need for treatment, do not blindly judge yourself.