Characterisation of a bleeding tendency requires multiple tests; however, a number of important factors can be elucidated clinically.
Differentiating between an inherited or acquired disorder may be suggested by the age. A full family history is also essential to establish any affected relatives.
Generalised haemostatic defects are suggested by bleeding from multiple sites, spontaneous bleeding and bleeding into the skin.
Bleeding disorders may result from abnormalities of blood vessels platelets and coagulation:
1. Vascular/platelet disorders are suggested by bruising, purpura and petechiae.
2. Inherited coagulation disorders are associated with haemarthroses (bleeding into the joints) and muscle haematomas.
Full blood count and blood film to examine the number and morphology of platelets.
Platelet aggregation times (spontaneous and stimulated) can be used to assess the function of platelets.
A full coagulation screen is performed comprising a prothrombin time (PT), thrombin time (TT) and ac-tivated partial thromboplastin time (APTT),.
Bleeding time is a measure of platelet function. A blood pressure cuff is applied and inflated to 40 mmHg. An incision is made that is 1-cm long and 1-mm deep. The time taken for bleeding to stop is measured. The bleeding time is prolonged in quantitative and qualitative platelet disorders.
Factor assays can be used to measure the levels of any components of the coagulation cascade.