1. Investigate the role of thromboelastometry (ROTEM) parameters in the prediction of bleeding events in thrombocytopenic patients.
2. Interpretation of platelet indices in thrombocytopenic patients and detection of their role in prediction of bleeding in these patients .
3. Examine the correlations between ROTEM parameters, platelet indices in thrombocytopenic patients .

Platelets are anucleate cells derived from megakaryocytes that play an important role in maintaining the integrity of the vascular endothelium and preventing haemorrhage. Adult platelet counts range from 150 - 450x10^3 / μL.The presence of a subnormal amount of platelets(<150 x 10^3 / μL)in circulating blood is referred to as thrombocytopenia, It is one of the most common haematological disorders and can become lifethreatening in case of severe disease. It could be due to a lack of platelet production or the degradation of platelets in the periphery. Hypoproliferative thrombocytopenias (aplastic anaemia, acute leukaemia) are one type of thrombocytopenia, while destructive thrombocytopenias (Idiopathic thrombocytopenia, secondry to SLE) are another. Bleeding is more likely in patients with severe thrombocytopenia.various reports have shown that platelet count is not a reliable predictor of clinically significant hemorrhage in thrombocytopenic patients Therefore, it may not be appropriate to use platelet count to guide treatment. Unfortunately, platelet function assays are often not sufficiently sensitive when platelet count is very low. As such, there remains the need to identify a predictor or set of parameters that can accurately assess the risk of hemorrhage in this patients.

The interpretation of platelet indices can aid in the initial care of thrombocytopenic patients ,Given the convenience and non-invasive nature of platelet indices calculation Although there are few studies in the literature on the significance of various platelet indices. the current study will be conducted to underline their importance in the diagnosis of thrombocytopenia.

Thromboelastography is a global coagulation test . The test is used to assess the change in elasticity over time of whole blood samples . Thromboelastography provides information about platelet function, coagulation, and fibrinolysis in just one assay monitoring.After improvement and automation, a thromboelastographic system known as ROTEM (rotational thromboelastometry) is now widely used in various clinical settings to determin the cause of bleeding in patients, evaluate bleeding risk, monitor the effect of anticoagulant drugs.and guide treatment.

The International Society on Thrombosis and Hemostasis (ISTH) is one of the well-known tools for bleeding assessment . The ISTH-BAT is a diagnostic questionnaire to screen patient depending on presence and absence of bleeding and also their severity.

Inclusion Criteria:

• Patients with thrombocytopenia and normal coagulation results
• Patients with and without significant bleeding events

Exclusion Criteria:

• patients with abnormal routine coagulation results (M3,liver diseases,........)
• patients who had received blood transfusions in the last 5 days.
• patients taking anticoagulant drugs or antiplatelet drugs .

• Patients diagnosed as hypoproliferative thrombocytopenias(aplastic anaemia, acute leukaemia) and destructive thrombocytopenias (Idiopathic thrombocytopenia, secondry) with platelet count < 50 x 103 / μL and normal coagulation results
• Patients with and without significant bleeding events