Clinical meaning
Therapeutic plasma exchange (TPE/plasmapheresis) removes the patient's plasma containing pathogenic autoantibodies, immune complexes, paraproteins, or toxins and replaces it with donor plasma or albumin solution. Each standard exchange removes approximately one plasma volume (40 mL/kg), eliminating roughly 63% of the target substance. Blood is drawn through a central venous catheter or large-bore peripheral access, separated by centrifugation or membrane filtration, the plasma is discarded, and cellular components are returned with replacement fluid. Category I ASFA indications (first-line therapy) include Guillain-Barré syndrome (anti-ganglioside antibodies), myasthenic crisis (anti-AChR antibodies), thrombotic thrombocytopenic purpura (TTP — removes anti-ADAMTS13 autoantibodies and replenishes ADAMTS13 enzyme), and anti-GBM disease (Goodpasture syndrome). Category II indications include acute demyelinating encephalomyelitis (ADEM), neuromyelitis optica (NMO), and severe lupus nephritis refractory to conventional therapy.
Diagnosis & workup
Diagnostics & workup: - Disease-specific autoantibody panels (anti-AChR, anti-GBM, ANCA, anti-ADAMTS13) - ADAMTS13 activity level and inhibitor titer for TTP diagnosis - Serum viscosity and quantitative immunoglobulins for hyperviscosity syndrome - CBC with differential, coagulation studies (PT/INR, PTT, fibrinogen) before each session - Ionized calcium level (citrate anticoagulant causes hypocalcemia during procedure) - Serum albumin and total protein to guide replacement fluid selection - Blood type and screen; hepatitis B/C and HIV serologies before initiating therapy