Which test is commonly used to monitor blood clotting?

The Prothrombin time (PT) test is commonly used to monitor blood clotting because it specifically assesses the blood's ability to clot properly and measures the time it takes for blood to coagulate. This test is particularly important for patients on anticoagulant medication, as it helps evaluate the effectiveness of these treatments and ensure that clotting levels remain within a safe range.

In contrast, the hematocrit test measures the proportion of blood volume that is made up of red blood cells, which is not directly related to clotting function. The comprehensive metabolic panel and the lipid panel are broader tests that evaluate various metabolic functions and cholesterol levels in the blood, respectively, but they do not directly assess blood coagulation. Therefore, the PT test is the most relevant and effective tool for monitoring blood clotting in clinical practice.