Understanding aPTT: Activated Partial Thromboplastin Time & What It Indicates

Activated partial thromboplastin time (aPTT) is a test that measures the time it takes for a blood clot to form after a substance called PTT reagent is added to blood plasma. The aPTT is a screening test for conditions that affect the blood's ability to clot, including hemophilia, von Willebrand disease, and lupus.

An elevated aPTT means that it took longer than normal for the blood clot to form. This could be due to a number of factors, including:

* Vitamin K deficiency

* Liver disease

* Kidney disease

* Disseminated intravascular coagulation (DIC)

* Antiphospholipid antibody syndrome

* Pregnancy

* Certain medications, such as heparin, warfarin, and aspirin

If your aPTT is elevated, your doctor will likely order additional tests to determine the cause.