 All patients will have standard haematological and biochemical blood tests as well having their ADAMTS 13 levels assessed. Regular blood tests will be arranged for patients discharged from hospital, to check their full blood count, electrolytes and liver function results and ADAMDTS 13 level. TTP patients will be reviewed initially weekly at their local out-patients clinic following discharge and as time passes and if their results are stable the period between appointments will be lengthened. 