Investigation of Investigation of HaemostasisHaemostasis

MS. c. programMS. c. program

Lab-9Lab-9

Functions of haemostasisFunctions of haemostasis

To maintain blood in a fluid state To maintain blood in a fluid state (within the vascular system).(within the vascular system).

To arrest bleeding at the site of To arrest bleeding at the site of injury or blood loss.injury or blood loss.

To ensure complete removal of the To ensure complete removal of the plug when healing is complete.plug when healing is complete.

Component of haemostasisComponent of haemostasis

Blood vessels.Blood vessels.Platelets (adhesion, aggregation, Platelets (adhesion, aggregation,

secretion, fusion).secretion, fusion).Plasma coagulation factors.Plasma coagulation factors.Plasma coagulation inhibitors.Plasma coagulation inhibitors.Fibrinolytic system.Fibrinolytic system.

Blood coagulationBlood coagulation

Coagulation pathways is the Coagulation pathways is the production of thrombin which acts production of thrombin which acts upon fibrinogen to produce fibrin and upon fibrinogen to produce fibrin and thus the fibrin clot.thus the fibrin clot.

Intrinsic and extrinsic pathway.Intrinsic and extrinsic pathway.

Sample collectionSample collection

Venous blood samples.Venous blood samples.Most commonly used anticoagulant Most commonly used anticoagulant

for coagulation samples is trisodium for coagulation samples is trisodium citrate.citrate.

Most routine used Platelet poor Most routine used Platelet poor plasma-ppp(2000g for 15min at 4c) plasma-ppp(2000g for 15min at 4c) except for platelet function testing except for platelet function testing (not be at 4c).(not be at 4c).

Screening testsScreening tests

Prothrombin time-PT.Prothrombin time-PT.Activated partial thromboplastin Activated partial thromboplastin

time-APTT(.time-APTT(.Thrombin time-TT.Thrombin time-TT.Bleeding time.Bleeding time.Fibrinogen titer.Fibrinogen titer.Platelet count.Platelet count.

Prothrombin time-PTProthrombin time-PTTest measures the clotting time of Test measures the clotting time of

plasma in presence of an optimal plasma in presence of an optimal concentration of tissue extract concentration of tissue extract (thromboplastin).(thromboplastin).

Extrinsic clotting system.Extrinsic clotting system.Normal range : 11-16s.Normal range : 11-16s.The common causes of prolonged The common causes of prolonged

PT (anticoagulant drugs, DIC, PT (anticoagulant drugs, DIC, Vitamin K deficiency and liver Vitamin K deficiency and liver disease).disease).

APTTAPTT Test measures the clotting time of plasmaTest measures the clotting time of plasma

after the activation of contact factors but after the activation of contact factors but without added tissue thromboplastin.without added tissue thromboplastin.

intrinsic clotting system.intrinsic clotting system. Normal range 30-40s.Normal range 30-40s. The common causes of prolonged The common causes of prolonged

APTT:DIC, massive transfusion with stored APTT:DIC, massive transfusion with stored blood and other couses. blood and other couses.

Thrombin timeThrombin time

Thrombin is added to plasma and Thrombin is added to plasma and clotting time measured.clotting time measured.

Within 2s.Within 2s.The common causes of prolonged TT.The common causes of prolonged TT.