The influence of blood platelet on fibrinolysis was studied mainly by euglobulin lysis technique and the following results were obtained:
1. The euglobulin lysis time (eug LT) of plasma samples was prolonged in storage at higher temperature than 0°C, but almost no change observed at -20°C.
2. Platelet was proved to have inhibitory influence on the fibrinolytic activity of plasmas or their euglobulin fractions, which seemed to have some direct relationship with the concentration of platelet.
3. Platelet adsorbed proactivator for plasminogen in plasma and released it during washing, and the washed platelet adsorbed again the proactivator in plasma at mixing with it.
4. Platelet material obtained through its destruction, also exhibited inhibitory influence on fibrinolysis.
5. The activated contact (XII. and XI.) factors for coagulation in plasma were affected by platelet easier than their inactive forms and this might be also one of the causes for depressed fibrinolytic activity in platelet rich plasma samples.
