What is pt

Remove the band from your arm when enough blood is collected. Put a gauze pad or cotton ball over the needle site as the needle is removed. Put pressure on the site and then put on a bandage.

How It Feels The blood sample usually is taken from a vein in your arm. Risks There is very little chance of a problem from having a blood sample taken from a vein. You may get a small bruise at the site. You can lower the chance of bruising by keeping pressure on the site for several minutes.

In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. A warm compress can be used several times a day to treat this. Results Prothrombin time PT is a blood test that measures how long it takes blood to clot. Normal The normal values listed here—called a reference range—are just a guide. It can also mean a lack of vitamin K; liver disease, such as cirrhosis ; or that a liver injury has occurred.

A longer-than-normal PT can also mean that you have disseminated intravascular coagulation DIC , a life-threatening condition in which your body uses up its clotting factors so quickly that the blood cannot clot and bleeding does not stop. A longer-than-normal PT can be caused by treatment with blood-thinning medicines, such as warfarin Coumadin or, in rare cases, heparin.

What Affects the Test Reasons you may not be able to have the test or why the results may not be helpful include: Taking medicines that can affect the action of warfarin and vitamin K.

These include antibiotics, cimetidine Tagamet , barbiturates, birth control pills, hormone therapy HT , and vitamin K supplements.

Having severe diarrhea or vomiting that causes fluid loss and dehydration. This may make the PT time longer. If diarrhea is caused by poor absorption of nutrients, vitamins, and minerals from the intestinal tract malabsorption syndrome , the PT may be longer because of a lack of vitamin K. Eating foods that have a lot of vitamin K. These include many green vegetables such as kale, spinach, collard greens, broccoli, and brussels sprouts. Drinking a lot of alcohol. Taking some herbal products or natural remedies.

What To Think About A PT is done at the same time of day each time so test results can check whether the right dose of warfarin is being used to prevent blood clots. Another blood clotting test, called partial thromboplastin time PTT , measures other clotting factors. Partial thromboplastin time and prothrombin time are often done at the same time to check for bleeding problems. To learn more, see the topic Partial Thromboplastin Time. Prothrombin levels are checked along with other liver tests, such as aspartate aminotransferase and alanine aminotransferase to check how the liver is working.

A Manual of Laboratory and Diagnostic Tests , 9th ed. Philadelphia: Wolters Kluwer Health. Laboratory Tests and Diagnostic Procedures, 6th ed.

Louis: Saunders. A Manual of Laboratory and Diagnostic Tests, 9th ed. Mosby's Manual of Diagnostic and Laboratory Tests, 5th ed. A change in the activity of any of the clotting factors. The absence of any of the clotting factors. Other substances, called inhibitors, that affect the clotting factors. An increase in the use of the clotting factors. Check the effects of warfarin Coumadin. You will have the test regularly to make sure you are taking the right dose.

Check for low levels of blood clotting factors. The lack of some clotting factors can cause bleeding disorders such as hemophilia , which is passed in families inherited. Check if it is safe to do a procedure or surgery that might cause bleeding.

Check how well the liver is working. Prothrombin levels are checked along with other liver tests, such as aspartate aminotransferase and alanine aminotransferase.

Check to see if the body is using up its clotting factors so quickly that the blood can't clot and bleeding does not stop. This may mean the person has disseminated intravascular coagulation DIC. How To Prepare In general, there's nothing you have to do before this test, unless your doctor tells you to.

How It Is Done A health professional uses a needle to take a blood sample, usually from the arm. How long the test takes The test will take a few minutes. How It Feels When a blood sample is taken, you may feel nothing at all from the needle.

Risks There is very little chance of having a problem from this test. Results Each lab has a different range for what's normal. It can also mean a lack of vitamin K; liver disease, such as cirrhosis ; or that a liver injury has occurred. This is a life-threatening condition in which your body uses up its clotting factors so quickly that the blood cannot clot and bleeding does not stop.

A longer-than-normal PT can be caused by treatment with blood-thinning medicines, such as warfarin or, in rare cases, heparin. A fingertip test may be done in a provider's office or in your home. During this test, you or your provider will:. If you are using an at-home test kit, you will need to review your results with your provider. Your provider will let you know how he or she would like to receive the results.

If you are taking warfarin, you may need to delay your daily dose until after testing. Your health care provider will let you know if there are any other special instructions to follow. There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

If you were tested because you are taking warfarin, your results will probably be in the form of INR levels. INR levels are often used because they make it easier to compare results from different labs and different test methods.

If you are not taking warfarin, your results may be in the form of INR levels or the number of seconds it takes for your blood sample to clot prothrombin time. If you are not taking warfarin and your INR or prothrombin time results were not normal, it may mean one of the following conditions:. Learn more about laboratory tests, reference ranges, and understanding results.

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health. What is it used for? Warfarin is a blood-thinning medicine that's used to treat and prevent dangerous blood clots.

Coumadin is a common brand name for warfarin. The test may be done on a blood sample from a vein or a fingertip.