reduced alpha2antiplasmin levels in the nephrotic syndrome venous and arterial thromboembolism frequently complicate the nephrotic syndrome increased platelet aggregation high levels of fibrinogen and other procoagulants and depressed levels of antithrombin iii and plasminogen are commonly cited as reasons less attention has been paid to changes in the hemostatic system which might protect against thrombosis we found a high frequency of reduced alpha 2antiplasmin levels in 40 patients with nephrotic syndrome correlating with serum albumin and with antithrombin iii levels since alpha 2antiplasmin is a major determinant of the sensitivity of fibrin thrombi to lysis and since reduced levels would be expected to promote fibrinolysis we conclude that in many patients with nephrotic syndrome depressed antiplasmin levels may help reduce the risk of thrombosis posed by diminished antithrombin iii levels