Blood is tested for clot lysis conditions such as natural lytic capabilities, the effect of previously administered thrombolytic and anti-thrombolytic agents, and dose responses thereto, by forming a clot in a sample of blood, lysing the clot, and measuring the elapsed time period from initial clot formation to clot lysis, all while continuously evaluating the blood sample. Thrombolytic agents include streptokinase, urokinase and recombinant tissue plasminogen activator. Plasmin and plasminogen activator inhibitors, clot activating agents (e.g. kaolin), and agents to deactivate anticoagulants (e.g. heparinase) may also be used as reagents during testing.