The Prothrombin Time (PT) test measures how long it takes for blood to clot. This test helps evaluate the presence of clotting disorders and is often used to monitor patients on anticoagulant medications, such as warfarin. Here's a brief breakdown:

Purpose: It assesses the function of certain clotting factors, which are proteins essential for blood clotting. If the clotting time is longer than normal, it could indicate a clotting disorder or the effect of blood-thinning medications.

How it Works: A blood sample is taken and mixed with a substance in the lab that triggers the clotting process. The time it takes for a clot to form is measured in seconds.

International Normalized Ratio (INR): Often, the PT test is reported with INR to standardize results across different labs, especially for patients on anticoagulants.