Final answer:
Prothrombin time (PT) and partial thromboplastin time (PPT) assess blood clotting; PT is for the extrinsic pathway, while PPT checks the intrinsic and common pathways. The International Normalized Ratio (INR) standardizes PT results, and Activated Partial Thromboplastin Time (APTT) is particularly important for monitoring heparin therapy.
Step-by-step explanation:
Prothrombin time (PT) and partial thromboplastin time (PPT) are both blood tests that evaluate the coagulation pathways. PT measures the time it takes for the blood to clot via the extrinsic pathway, which is activated by external trauma that causes blood to escape from the vascular system. This test is sensitive to certain blood thinners and deficiencies in clotting factors. The International Normalized Ratio (INR) is a standardized way of expressing the PT, allowing for the comparison of results across different labs and equipment. A higher INR indicates a longer clotting time.
Activated Partial Thromboplastin Time (APTT) assesses the efficiency of the intrinsic and common coagulation pathways. The intrinsic pathway is longer and more complex, involving factors present within the bloodstream, and is initiated by internal factors such as arterial disease or the presence of foreign materials. APTT is particularly important in monitoring heparin therapy.
These coagulation tests are essential in assessing bleeding disorders, liver disease, and the efficacy of anticoagulant drugs like thrombolytic agents, which can help degrade abnormal blood clots. The liver produces coagulation factors, so these tests can also gauge liver function