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Activated Partial Thromboplastin Time (aPTT) Blood Test

* This is not a home test kit. You will need to visit a local lab for testing.

Also Known As

Partial Thromboplastin Time, aPTT, PTT

The Purpose of an aPTT Test

Partial thromboplastin time (PTT) refers to the length of time it takes for your blood to clot, and a PTT test is the starting point for investigating excessive bleeding and clotting disorders. It is also used to monitor heparin anticoagulant therapy and to distinguish if the right doses of heparin are being administered. Also, this test helps assess the risk of excessive bleeding before surgeries.

Partial Thromboplastin Time, Activated aPTT (763)
Partial Thromboplastin Time, Activated aPTT (005207)

What Does the PTT Blood Test Measure?

The aPTT lab test measures how well your body’s blood clotting process is working. Each factor in the clotting process must be working properly and be present in the right amount. If there is not enough of one or more factors, or if the factors are not functioning correctly, excessive bleeding or clotting may occur.

Who Should Take a Partial Thromboplastin Time Test?

Your doctor can use the aPTT blood test to monitor your treatment if you are on the anticoagulant heparin or help diagnose a coagulation factor deficiency that could be causing unusual blood clotting. Testing may also help assess the severity of the liver disease.

aPTT Test Preparation

If you’re currently undergoing heparin treatment, your blood specimen should be collected one hour before your next heparin dose. The blood sample must be collected from the arm that doesn’t have the heparin lock/catheter.

PTT Blood Test Results

Because the aPTT lab tests time how long it takes your blood to clot, the results are measured in seconds. For most people, the normal range is 30 to 40 seconds; if you’re on heparin, the time should be 60 to 80 seconds. Your doctor may want to order more testing, depending on the results.

Where Can I Get a PTT Test Near Me?

If you’re experiencing unexplained blood clotting, get the answers you need from Personalabs. A partial thromboplastin time test is one of more than 400 health tests you can shop for online. We’ve streamlined the process for getting a blood test so you receive fast, accurate results:

Step 1: Purchase your test from Personalabs and download the corresponding lab order. (Don’t worry about getting your doctor’s approval beforehand; you may not need it, depending on the state where you live.)

Step 2: Use the lab locator on our website to sort through our 4,000-plus partner facilities across the country and find the one that’s most convenient for you. We work with Labcorp and Quest Diagnostics, two of the country’s top lab companies.

Step 3: Get your blood drawn. (Be sure to bring the test order with you to the lab.)

Step 4: Look for your results to arrive in your private Personalabs portal anytime between 2 and 10 business days after your test. Need the results on a specific date? Contact us so we can reach out to the lab on your behalf. And if you need to discuss your results with a board-certified physician, simply schedule a telehealth visit with one of our Personalabs doctors.

Browse our wide range of tests to discover the many ways Personalabs can help you take charge of your health.

Additional information


LabCorp, Quest

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Results can be provided in as little as 24-48 hrs. For more complex tests, please contact us for turn around times.


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