Often referred to as BT/CT. Bleeding / Clotting Time Tests are used to identify any disorders related to blood hemostasis. Bleeding time is the measure of the time taken for the bleeding to stop as a function of the platelet aggregation to form a plug and constriction of blood vessels. Bleed time test helps identify any disorder associated with the functioning of the platelets. Clotting time is the measure of the time taken in the formation of a clot after the bleeding has started. Clotting is the function of the enzyme thrombin, its precursor prothrombin, and clotting factors; hence, the clotting time test helps in the diagnosis of various disorders related to clotting factors or deficiency of vitamin K. A partial thromboplastin time (PTT) test measures the time it taken for a blood clot to form. Normally, when you get a cut or injury that causes bleeding, proteins in your blood called coagulation factors work together to form a blood clot. The clot stops you from losing too much blood.