APTT Test (Activated Partial Thromboplastin Time)

APTT test measured to investigate a bleeding or thrombotic episode. It helps evaluate the risk of excessive bleeding prior to a surgical procedure. Also, to monitor heparin anticoagulant therapy.

Your health practitioner may recommend aptt test for you if you show symptoms of prolonged and excessive bleeding which includes:

• Frequent nosebleeds
• Blood in urine
• Heavy menstruation for women
• Painful and swollen joints
• Easy bruising

The activated partial thromboplastin time is a functional measure of the intrinsic and usual pathways of the clotting cascade. To form blood clots, to seal off injuries, to blood vessels and tissue, to restrict further blood loss, and to give the damaged areas time to seal the body using the coagulation cascade. The cascade contains a group of clotting factors. These proteins are activated serially along either the extrinsic or intrinsic pathways.

The branches then come together into the common pathway, and complete their task with the formation of a steady blood clot. These three pathways have to work when a person starts bleeding. Each component of the coagulation cascade must be working properly and be present in enough quantity for normal blood formation. Stable clot formation will be inhibited and excessive bleeding and/or clotting may occur if there is an inherited or assimilated deficiency in one or more of the factors, or if the factors are functioning unusually. The aptt test measures the amount of time that it takes for clotting to happen when reagents are added to plasma in a test tube.

The test is required in cases of : 
- Suspected problems with 1 or more clotting factors. 
-Bleeding disorders, such as von Willebrand disease or another disease that prevents your blood from clotting.
-To monitor people who are getting heparin therapy. Heparin is a blood thinner used to prevent dangerous blood clots. 

The test calculates the APTT in the blood. 

The test requires a blood sample. A tourniquet (elastic) band is placed tightly on the upper arm. The patient is then asked to make a fist. This helps in the build-up of blood filling the veins. The skin is disinfected before needle insertion and the blood sample is collected in vacutainer. 

Prolonged APTT tests may be due to inherited or acquired factor deficiencies,  lupus anticoagulant (LA), DIC, fibrinolysis, cirrhosis, malabsorption, and liver diseases. APTT levels may also be affected in patients on anti-coagulant therapy.