Background.Serum soluble urokinasetype plasminogen activator receptor(suPAR)is implicated in the pathogenesis of native and recurrent FSGS.It is elevated in two-thirds of subjects with primary FSGS,but not in people with other glomerular diseases which can differentiate FSGS and other glomerular diseases.Methods.we measured soluble urokinase receptor levels in the resum of patients with primary focal segmental glomerulosclerosis(FSGS)and determined their association with clinical and pathological data in 86 patients with primary FSGS,5 repeat renal biopsy FSGS and 6 recurrent FSGS posttranplantation,healthy controls and patients with minimal change disease,and membranous nephropathy were used as controls.The suPAR levels,measured by commercial ELISA kits.Results.of patients with primary FSGS were significantly higher than those of patients with minimal change disease,membranous nephropathy,and healthy individuals.There was no significant difference in suPAR levels between the 65 patients with minimal change disease and 85 patients with membranous nephropathy.The suPAR levels increased in the 5 repeated renal biopsy FSGS and 6 recurrent FSGS posttranplantation.Conclusions.The suPAR levels were significantly but positively correlated with FSGS,not only primary FSGS but also recurrent FSGS posttransplantation,but negatively correlated with other glomerular diseases.Thus,suPAR levels can differentiate primary FSGS and other glomerular diseases.