A) Coagulation screening test
1. Prothrombin time test (PT)
Purpose: The PT is a widely used laboratory assay for the detection of inherited or acquired coagulation defects related to the extrinsic pathway of coagulation.PT test was carried out to determined how quick the blood to clots usually with the present of extrinsic factor especially present of factor VII, V, and X, prothrombin, and fibrinogen. Prothrombin or factor II is a protein that produced by the liver which need the present of vitamin K and also to produce other clotting factors. This test is crucial to determine the present of other different blood clotting factors such as factors I, II, V, VII, and X. A prolonged prothrombin time indicates a deficiency in any of factors VII, X, V, prothrombin, or fibrinogen and also associated with deficiency of vitamin K (The McGill Physiology Virtual Lab, n.d). PT is also used for monitoring oral anticoagulant (warfarin) because of its sensitivity to changes in the concentration vitamin-K dependent factors (factors II, VII, and X).…show more content… The test is performed by adding the patient’s plasma to source of tissue factor which then converts prothrombin to thrombin. For about one to two minutes the mixture is then kept in warm water bath at 37⁰C. Calcium chloride (excess quantities of ionized calcium) is added to the mixture in order to counteract the sodium citrate and allow clotting to start. The test is timed from the addition of the calcium chloride until the plasma clots. This time is called the Prothrombin Time (The McGill Physiology Virtual Lab,