Asked by: Yumalay Clavier
asked in category: General Last Updated: 28th March, 2020

What does aPTT measure?

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.

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Also to know is, what does a high aPTT mean?

A prolonged aPTT usually means that clotting is taking longer to occur than expected (but is associated with increased risk of blood clots if due to a lupus anticoagulant) and may be caused by a variety of factors (see the list below). Coagulation factor deficiencies may be acquired or inherited.

Additionally, what is the difference between aPTT and PTT? 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. The result is always compared to a control sample of normal blood.

Likewise, what factors does aPTT measure?

The aPTT evaluates factors I (fibrinogen), II (prothrombin), V, VIII, IX, X, XI and XII. (A retrospective study by Bachler et al indicated that in critically ill patients, a factor XII level of 42.5% or less leads to spontaneous prolongation of aPTT.)

What does it mean when your aPTT is low?

A decreased aPTT may result when coagulation Factor VIII is elevated. This may occur during an acute phase reaction - the blood's reaction to acute tissue inflammation or trauma. This is usually a temporary change that is not monitored with the aPTT.

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