Haemophilia A is a bleeding disorder resulting from a deficiency of blood coagulation factor VIII (FVIII) of the coagulation cascade. Patients with severe haemophilia A can experience spontaneous intramuscular, gastrointestinal and intracranial bleeds and recurrent joint bleeds. Patients with mild or moderate haemophilia A can experience severe bleeding episodes in response to surgery or trauma.To reduce bleeding risk, haemophilia patients are treated with FVIII replacement therapy. However, some patients may develop antibodies to their replacement FVIII, leading to bleeding complications that can be difficult to correct. Moreover, haemophilia patients may exhibit accelerated FVIII clearance such that they require additional or larger FVIII infusions. This study will focus on the development of tests to evaluate blood coagulation using plasma from both individuals with haemophilia and pre-clinical mouse models of haemophilia, in an effort to better identify factors modulating individual patient bleeding tendency. Collectively, this study will help develop better approaches towards predicting bleeding risk in patients with severe bleeding disorders.