Prothrombin time (PT) is a commonly used indicator to screen whether the exogenous coagulation pathway is normal or not. The clotting time of the examined plasma is observed and measured by adding calcium ions, tissue factor or tissue thromboplastin to the examined plasma.
When PT is prolonged, it is common in congenital coagulation factor deficiency, severe liver disease, hyperfibrinolysis, DIC and other diseases; while PT is shortened, it usually suggests that the blood is in a hypercoagulable state, such as myocardial infarction, deep vein thrombosis, and the early stage of DIC and other diseases.
Platelets do not participate in the blood coagulation process, but are mainly associated with physiological hemostasis and thrombosis. Platelet abnormalities are usually determined by platelet counting tests and by observing the morphology of platelets in the peripheral blood.