General	High risk clinical situations	Diseases associated with a prothrombotic state	Inherited thrombophilia
Older age Immobility, paresis Malignancy Obesity Family history of VTE Oral contraceptive pill, hormone replacement, tamoxifen Venous insufficiency or varicose veins	Surgery (especially hip and knee surgery or major surgery for malignancy) Pregnancy/puerperium Acute medical illness Congestive cardiac and respiratory failure Trauma Central venous catheter	Myeloproliferative disorders Antiphospholipid syndrome Paroxysmal nocturnal haemoglobinuria Nephrotic syndrome Hyperviscosity syndrome Inflammatory bowel disease	Factor V Leiden mutation Antithrombin, protein C and protein S deficiency Prothrombin gene mutation (Factor II G20210A mutation)