The frequency of plasma exchange depends on the type of disease, the severity of the disease, and the concentration of the causative factor, but patients are usually required to have plasma exchange once a day or once every other day, at least 5 times. For example, in pulmonary hemorrhage-nephritis syndrome, plasma exchange should be done once a day for the first week, and the amount of plasma to be exchanged each time is 1-2 plasma volumes. If the disease is in remission for the 2nd week, plasma exchange can be done every other day to reduce the patient’s disease-causing factor-anti-GBM antibodies to normal levels and alleviate the disease. For hematologic diseases such as thrombotic thrombocytopenic purpura, plasma exchange is recommended to be done once a day for the first 1 week, with 1-2 plasma volumes per exchange until the disease is in complete remission.