Thrombotic thrombocytopenic purpura is a less common form of microvascular haemolysis and is often associated with kidney damage, fever and neuropsychiatric symptoms. Laboratory tests performed in patients with this condition include blood tests, which show varying degrees of anaemia and low platelet counts, as well as blood biochemistry and coagulation tests, and testing for ADAMTS13 gene activity can provide an important basis for the diagnosis of the disease. Patients can be diagnosed by the characteristic presentation as well as by relevant tests.