Prothrombin Time with INR Test

Prothrombin Test (PT), also known as Pro Time Test, is a blood test that measures how long it takes for blood to clot. Often used for identifying bleeding problems, it is also used to check if medicines (mostly Warfarin) that prevent blood clots are effectively working. A PT test is referred to as an INR Test, where INR stands for International Normalised Ratio and is a method of standardizing the results of the Prothrombin Test, irrespective of the testing method. This can be done using the INR System and enables the doctor to analyse reports from different labs. Prothrombin Test is important as it checks for the presence of five different blood clotting factors (factors I, II, V, VII, and X). Prothrombin or Factor II is made by the liver aided by a sufficient amount of Vitamin K. A doctor suggests a PT Test for symptoms such as excessive bleeding, bleeding gums, blood in urine or stool, heavy periods for women, bone marrow and liver problems, Vitamin K deficiency and leukemia.

You might have to avoid certain foods which affect the functioning of the liver like broccoli, kale, green tea and soy products which will be intimated to you in prior by your doctor. In case you are on warfarin, you will have to take the test before your day’s dose. Preferably wear a sleeveless or a short sleeved shirt. Hence, the test does not call for cumbersome requirements.

Once the results arrive from the research laboratories, as aforementioned, it will specify the time taken for your blood to clot. The average blood clotting time is 10-14 seconds. A higher number indicates:

an abnormal amount of Vitamin K in your body malfunctioning of the liver blood clotting disorder ineffective functioning of warfarin A lower indicates fast blood clotting which could be due to supplements or foods rich in Vitamin K.

It is a basic blood draw test where the lab technician will:

Use an alcohol pad to clean the skin where the needle goes in. The thin needle is injected into a vein usually at the inside of your arm at your elbow. The blood is sucked into the needle by a nozzle, and stored in a sealed container with your name. Since blood is drawn, there is a slight chance of bleeding or dizziness.