What does PT/INR measure in blood tests?

PT/INR, which stands for Prothrombin Time/International Normalized Ratio, is a test that measures how long it takes for blood to clot. This test is particularly important for evaluating the extrinsic pathway of coagulation and can be crucial in managing patients who are on anticoagulant therapy, such as warfarin. The PT component reflects the time it takes for clot formation after adding a tissue factor to the sample, while INR standardizes the results to account for variations in test performance and reagents used in different labs.

Assessing clotting time is essential for diagnosing bleeding disorders and monitoring patients' responses to anticoagulation therapy. Abnormal PT/INR values can indicate a variety of conditions, including liver dysfunction, vitamin K deficiency, or the presence of certain clotting factor deficiencies. Thus, this test is a key tool within laboratory medicine for ensuring safe and effective patient care regarding blood coagulation.