Final answer:
PTT stands for Partial Thromboplastin Time, a test measuring the time for clot formation in blood, assessing the intrinsic and common coagulation pathways including the conversion of prothrombin to thrombin.
Step-by-step explanation:
The acronym PTT stands for Partial Thromboplastin Time. It is a laboratory test used to evaluate the activation of the intrinsic pathway and the activation of the common pathway of coagulation. Specifically, the PTT test measures the time it takes for a clot to form in a blood sample after substances (reagents) are added to activate the intrinsic coagulation pathway. This pathway is part of the complex process that leads to the conversion of fibrinogen to fibrin, which is essential for blood clot formation. During coagulation, Prothrombin is converted to thrombin, an important step in the clotting process that the PTT test indirectly assesses through its measurement of clot formation time.