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Prothrombin Time

What is it?

A prothrombin (pro-THROM-bin) time, or "pro-time", is one of the blood tests done to see how fast your blood clots. Prothrombin is a protein produced by the liver that helps blood clot. To clot means the blood goes from liquid to solid. You may need to have this test done more than one time.

Why do I need it?

  • A pro-time may be done if you have a problem with bleeding.
  • If you are taking blood thinners, it is done to see how your medicine is working. People may respond differently to the same dose of blood thinner medicine. Your doctor will carefully keep track of your pro-time results. These results will help your doctor decide the right kind and amount of medicine you should be taking.

How do I get ready for the test?

Your caregiver will tell you when you need to have your blood taken. The blood test may be done before or after eating.

How is the blood collection done?

A caregiver will put a wide rubber strap around your arm and tighten it. Your skin will be cleaned with alcohol. A small needle attached to a special test tube will be put into a vein in your arm or hand. The tube has suction to pull the blood into it. When the tube is full, the rubber strap, needle and tube are removed. The caregiver will press a piece of cotton where the needle was removed. You may be asked to hold the cotton on the site for a few minutes to help stop the bleeding. Tape may then be put over the cotton on your arm.

What do I do after the test?

You may remove the tape and cotton in about 20 to 30 minutes. Call your caregiver to get the results of your test. Your caregiver will explain what your test results mean for you. Follow the instructions of your caregiver.

Care Agreement

You have the right to help plan your care. To help with this plan, you must learn about your lab tests. You can then discuss the results with your caregivers. Work with them to decide what care may be used to treat you. You always have the right to refuse treatment.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.