This plasma is an ideal negative control for ELISA based assays and other experiments involving PAI-1. Collected from homozygous PAI-1 knockout mice of strain B6.129S2- Serpine1 tm1Mlg /J. Anticoagulated with sodium citrate and flash frozen. The targeted PAI-1 knockout mutation was made on the C57BL/6J background strain. Mice homozygous for this mutation develop normally and are viable and fertile. Compared to wild type mice, pulmonary clot lysis is increased in the heterozygote and further increased in the homozygote. Endotoxin induced venous thrombosis is decreased compared to wild type mice. Thus, disruption of the Serpine1 gene induces a mild hyperfibrinolytic state. Hemostasis is normal in homozygous mutants.