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Prothrombin Time (PT) and Partial Thromboplastin Time (PTT) Tests

Lab order in a few minutes

Lab order
in a few minutes

Low prices since 2005

Low prices
since 2005

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90 day money-back
guarantee

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No waiting
at the doctor's

Labs within 2 miles

Labs within
2 miles

Private, accurate and secure

Private, accurate
and secure

Private MD Lab Services offers the following test for prothrombin time:

Prothrombin Time (PT) (INR) and Partial Thromboplastin Time (PTT) (LabCorp) Next Day Results*
You earn: 72 pts
HSA/FSA accepted

What is the prothrombin time test?

The prothrombin time, or PT, test measures the time it takes your blood to form a clot. This test is also often called protime.

The results of the prothrombin time test may vary from lab to lab, so health care providers use a ratio called the INR (international normalized ratio) to be able to account for the differences.

Why is this test done?

The PT/INR is usually done to measure the effect of blood-thinning medicines (anticoagulants), such as warfarin (Coumadin).

If you have a medical condition such as atrial fibrillation or deep vein thrombosis, or have had a heart valve replaced, your blood is more likely to form clots. Clots can block blood vessels and possibly cause a heart attack or stroke. Your health care provider may prescribe a blood thinner to help prevent clots. It's very important to measure the effect of a blood thinner with this test. The medicine should keep the blood just thin enough to prevent clots. If the blood is too thin, you may bleed too easily.

The prothrombin time test may also be done if you have abnormal bleeding or clotting.

How do I prepare for this test?

  • You may need to avoid taking certain medicines before the test because they might affect the test result. Make sure your health care provider knows about any medicines, herbs, or supplements that you are taking. Don't stop any of your regular medicines without first consulting with your health care provider.
  • If you are taking warfarin (Coumadin), having different amounts of vitamin K in your diet from day to day can affect your test results and the Coumadin dosage that you need. For example, leafy green vegetables, such as spinach, and oils such as canola oil and soy bean oil, are some of the foods that have high amounts of vitamin K. If you are on warfarin, you should eat a healthy balanced diet with about the same amount of vitamin K each day. Follow your health care provider's instructions for your diet.

How is the test done?

A small amount of blood is taken from your arm with a needle. The blood is collected in tubes and sent to a lab.

Having this test will take just a few minutes of your time. There is no risk of getting AIDS, hepatitis, or any other blood-borne disease from this test.

How will I get the test result?

Ask your health care provider when and how you will get the result of your test.

What does the test result mean?

The normal PT range is 11 to 14 seconds. The normal range may vary slightly from lab to lab. Normal ranges are usually shown next to your results in the lab report.

A PT value higher than normal means your blood is taking longer than usual to form a clot. This prolonged PT may happen if:

  • You are taking warfarin.
  • You have liver disease.
  • You need more vitamin K.
  • You have an inherited blood disorder.
  • You have had a lot of heavy bleeding recently.

The normal value for the INR is 1.0

The INR is used to adjust the dose of warfarin. The desired INR will vary depending on what condition is being treated.

What if my test results are not normal?

Test results are only one part of a larger picture that takes into account your medical history and current health. Sometimes a test needs to be repeated to check the first result. Talk to your health care provider about your result and ask questions.

If your test results are abnormal, ask your health care provider:

  • if you need additional tests
  • what you can do to work toward a normal value
  • when you need to be tested again.

Copyright © 2006 McKesson Corporation and/or one of its subsidiaries. All Rights Reserved.

FAQ

  1. What is a PT and PTT blood test?

    Both PTT and PT are tests used for measuring the time taken for the blood to clot. PT is used to measure extrinsic coagulation (clotting factors, warfarin levels, and vitamin K position), while PTT measures intrinsic coagulation (different clotting factors, heparin levels).

  2. What do PT and PTT test for?

    PT and PTT are routinely used before surgery to evaluate the risk of excessive bleeding that may lead to surgery complications. PT and PTT can also help detect bleeding disorders such as:

    • Myocardial infarction or heart disease
    • Bleeding disorders
    • Platelet disorders
  3. Why should I get a PT and PTT test?

    To prevent surgery complications due to excessive bleeding, a PT and PTT test should be performed. Also, having this test is convenient if you are presenting blood clotting disorders symptoms, such as:

    • Heavy bleeding from small cuts
    • Easy bruising
    • Bleeding gums
    • Unexplained nosebleeds
    • Heavy menstrual bleeding, and for longer than 7 days

    If your results for PT and PTT are abnormal, speak to your doctor for guidance on further testing and treatment options.

  4. When should I get a PT and PTT test?

    This test is recommended when you have:

    • Suspicion of a bleeding disorder
    • Abnormal healing time after surgery
    • A programmed surgery
    • Had a blood transfusion recently
    • Been taking blood thinning medicines
    • Hemophilia
  5. Does PT or PTT testing require fasting?

    You do not need to fast before these tests.

  6. Do I need to visit a doctor?

    Nope. You don't need a doctor's visit to get a test with us.

  7. How do I get my results?

    You'll get your results via email as soon as they are available. We will notify you via SMS as well. You can also see them at any time in the future right in your dashboard where you can easily share them with your professional and compare them side by side with future tests.

  8. Does my lab prescription expire?

    We're the only lab that honors your lab order forever.

Questions about online blood testing or how to order a lab test?

Speak with our Wellness Team: (877) 283-7882
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