Final answer:
The international normalized ratio (INR) test measures the time taken for clot formation. An increased INR indicates a longer time for blood to clot. This test is commonly used to monitor the effectiveness of blood thinning medications.
Step-by-step explanation:
A test that measures the amount of time taken for clot formation is called the international normalized ratio (INR) test. The INR measures the speed of a specific pathway of coagulation in the blood, comparing it to normal clotting time. If the INR is increased, it indicates a longer time for blood to clot. This test is commonly used to monitor the effectiveness of blood thinning medications.