The activated partial thromboplastin time (aPTT or TTPa in Spanish) is a crucial coagulation test that evaluates the intrinsic and common pathways of the coagulation cascade. It measures the time it takes for a blood sample to clot after specific reagents are added. This test assesses the function of various clotting factors (specifically factors VIII, IX, XI, XII, X, V, II [prothrombin], and I [fibrinogen]) and helps identify potential bleeding disorders or hypercoagulable states. It is a fundamental tool for monitoring heparin therapy.
aPTT
Intrinsic coagulation pathway.