Combinations of increased thrombin, plasmin and non-specific protease activity in patients with acute leukaemia.

Thrombin generation, plasmin formation and non-specific protease activity, were assessed in a cohort group of 30 patients presenting with acute leukaemia. Abnormalities detected by specific tests of one or more of these three systems were found in 27 (90%) of patients while abnormalities in 'routine' laboratory coagulation tests were seen in only 17 (56%). All patients at presentation had a bleeding tendency which was defined as minor (skin purpura) or major (other bleeding sites). Patients presenting with minor (n = 19) or major haemorrhage (n = 11) could not be differentiated by the degree of thrombocytopenia. Similarly, increased generation of either thrombin or plasmin activity alone was non-discriminatory. However, more complex alterations of haemostasis involving increased activity of more than one of these three systems were seen only in those patients who had major haemorrhage.