1. Investigation of Haemostasis MS. c. program Lab-9

2. Functions of haemostasis To maintain blood in a fluid state (within the vascular system). To maintain blood in a fluid state (within the vascular system). To arrest bleeding at the site of injury or blood loss. To arrest bleeding at the site of injury or blood loss. To ensure complete removal of the plug when healing is complete. To ensure complete removal of the plug when healing is complete.

3. Component of haemostasis Blood vessels. Blood vessels. Platelets (adhesion, aggregation, secretion, fusion). Platelets (adhesion, aggregation, secretion, fusion). Plasma coagulation factors. Plasma coagulation factors. Plasma coagulation inhibitors. Plasma coagulation inhibitors. Fibrinolytic system. Fibrinolytic system.

4. Blood coagulation Coagulation pathways is the production of thrombin which acts upon fibrinogen to produce fibrin and thus the fibrin clot. Coagulation pathways is the production of thrombin which acts upon fibrinogen to produce fibrin and thus the fibrin clot. Intrinsic and extrinsic pathway. Intrinsic and extrinsic pathway.

5. Sample collection Venous blood samples. Venous blood samples. Most commonly used anticoagulant for coagulation samples is trisodium citrate. Most commonly used anticoagulant for coagulation samples is trisodium citrate. Most routine used Platelet poor plasma- ppp(2000g for 15min at 4c) except for platelet function testing (not be at 4c). Most routine used Platelet poor plasma- ppp(2000g for 15min at 4c) except for platelet function testing (not be at 4c).

6. Screening tests Prothrombin time-PT. Prothrombin time-PT. Activated partial thromboplastin time- APTT(. Activated partial thromboplastin time- APTT(. Thrombin time-TT. Thrombin time-TT. Bleeding time. Bleeding time. Fibrinogen titer. Fibrinogen titer. Platelet count. Platelet count.

7. Prothrombin time-PT Test measures the clotting time of plasma in presence of an optimal concentration of tissue extract (thromboplastin). Test measures the clotting time of plasma in presence of an optimal concentration of tissue extract (thromboplastin). Extrinsic clotting system. Extrinsic clotting system. Normal range : 11-16s. Normal range : 11-16s. The common causes of prolonged PT (anticoagulant drugs, DIC, Vitamin K deficiency and liver disease). The common causes of prolonged PT (anticoagulant drugs, DIC, Vitamin K deficiency and liver disease).

8. APTT Test measures the clotting time of plasma after the activation of contact factors but without added tissue thromboplastin. Test measures the clotting time of plasma after the activation of contact factors but without added tissue thromboplastin. intrinsic clotting system. intrinsic clotting system. Normal range 30-40s. Normal range 30-40s. The common causes of prolonged APTT:DIC, massive transfusion with stored blood and other couses. The common causes of prolonged APTT:DIC, massive transfusion with stored blood and other couses.

9. Thrombin time Thrombin is added to plasma and clotting time measured. Thrombin is added to plasma and clotting time measured. Within 2s. Within 2s. The common causes of prolonged TT. The common causes of prolonged TT.