What is aPTT blood test used for?

The partial thromboplastin time (PTT; also known as activated partial thromboplastin time (aPTT)) is a screening test that helps evaluate a person’s ability to appropriately form blood clots. It measures the number of seconds it takes for a clot to form in a sample of blood after substances (reagents) are added.

What does it mean when aPTT is high?

An increased activated partial thromboplastin time (aPTT), when the patient is not on anticoagulant therapy (heparin, warfarin, etc.) signifies a bleeding disorder. It takes the blood more time to form a blood clot and therefore there is a prolonged bleeding time when there is a hemorrhage.

What is the difference between PTT and aPTT?

Partial thromboplastin time (PTT) and activated partial thromboplastin time (aPTT) are used to test for the same functions; however, in aPTT, an activator is added that speeds up the clotting time and results in a narrower reference range.

What does aPTT and PT measure?

Tests of the Coagulation Cascade. These in vitro tests—the activated partial thromboplastin time (aPTT), prothrombin time (PT), and thrombin time (TT)—measure the time elapsed from activation of the coagulation cascade (Figure 157.1) at different points to the generation of fibrin.

What is a normal aPTT?

A normal range is around 25 to 35 seconds, but test results will vary depending on equipment and methods used. Therefore, standard normal results will differ in each lab. If your aPTT takes longer than usual, it may mean several things.

What does it mean when aPTT is low?

What does a low activated partial thromboplastin time (aPTT) in a blood test mean? A low activated partial thromboplastin time (aPTT) show that blood is clotting faster than normal and that increases the risk to develop a blood clot.

What is normal aPTT range?

What is the normal aPTT ratio?

Most medical textbooks and many experts recommend a therapeutic range of 1.5 to 2.5 times the control value (the mean aPTT obtained by testing a minimum of 20 plasma samples from healthy persons).

How is aPTT measured?

Blood is drawn into a test tube containing oxalate or citrate, molecules which act as an anticoagulant by binding the calcium in a sample. The blood is mixed, then centrifuged to separate blood cells from plasma (as partial thromboplastin time is most commonly measured using blood plasma).

What is normal range of aPTT?

How do you read aPTT results?

A typical aPTT value is 30 to 40 seconds. If you get the test because you’re taking heparin, you’d want your PTT results to be more like 120 to 140 seconds, and your aPTT to be 60 to 80 seconds. If your number is higher than normal, it could mean several things, from a bleeding disorder to liver disease.