Your blood contains several substances that cause it to clot when you get a cut or other injury. Clotting tests help determine if you are at risk for blood clots or bleeding disorders. If you take a blood thinner such as heparin or warfarin, clotting tests are used to monitor your progress. If you have an abnormal test result, you might have to increase or decrease the dosage of your medication to prevent clotting or bleeding problems. *This test is sent out to an outside lab and takes 24-48 hours to get back the results