Activated Partial Thromboplastin Time (APTT)Test

What is this test?


The aPTT is one of several blood coagulation tests. It measures how long it takes your blood to form a clot.

Normally, when one of your blood vessels is damaged, proteins in your blood called clotting factors come together in a certain order to form blood clots and quickly stop bleeding. The aPTT test can be used to look at how well those clotting factors are working. It’s often used with other tests that monitor clotting factors.

Blood clots form in a specific series of steps called a pathway. This test mainly looks at how both the intrinsic clotting pathway and the common final pathway are working.


Why do I need this test?


You may need this test if your healthcare provider believes that you have a problem with 1 or more clotting factors. If you have a bleeding disorder such as von Willebrand disease or another disease that prevents your blood from clotting, this test can help find out where the problem is.This test is also used to monitor people who are getting heparin therapy. Heparin is a blood thinner used to prevent dangerous blood clots. 


What do my test results mean?


Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Your test results may not mean you have a problem. Ask your healthcare provider what your test results mean for you. 

Test results are measured in seconds of time. Your results will show how long your blood took to clot, and will often compare them with results from a normal sample tested at the same time. A normal range is around 21 to 35 seconds. But test results will vary depending on equipment and methods used. So standard normal results will differ in each lab. If your aPTT takes longer than normal, it may mean several things. Often other tests are done at the same time as the aPTT to better find out which factors are involved.


How is this test done?


The test is done with a blood sample. A needle is used to draw blood from a vein in your arm or hand. At  SOUTH PUNJAB LAB this test is performed on COADATA.


What might affect my test results?


Certain medicines may affect the results of this test. These include heparin and large doses of warfarin (Coumadin). If you are taking these medicines, follow your healthcare provider’s instructions. Your provider may want you to stop taking them before the test.