Indications and contraindications for plasma exchange are as follows: 1. Indications: including severe impairment of renal function due to acute nephritis, etc.; multiple immune diseases; autoimmune hemolytic anemia; thyroid crisis such as hepatic encephalopathy; acute and chronic rejection after renal transplantation; acute drug or toxic poisoning, etc. 2. Relative contraindications: including severe allergy to heparin, etc.; systemic circulatory failure that is difficult to be corrected by drugs; non Stable cardiac and cerebral infarction; cerebral hemorrhage or severe cerebral edema with brain herniation; mental disorders; severe bleeding and clotting disorders, etc.