APTT/PTT can be ordered along with PT - INR in following conditions antSicoagulant. It is also ordered in patients who show symptoms of bleeding disorders like -
The APTT is functional determination of the intrinsic pathway of coagulation. (Factors XII, XI, IX, VIII, V, II, I, prekallikrein, high molecular weight kininogen).
Prolonged in - Haemophilia A or B
Additional test- ordered along with APTT to follow the abnormal results.
PT - determine the functional activity of extrinsic factors of coagulation pathway.( link PT )
Platelet count - low platelet count predispose to bleeding. (link platelet count )
Fibrinogen test - low fibrinogen level predispose to bleeding.
Von Willebrand factor - to rule out von Willebrand disease.
Coagulation factors - factor levels provide in depth analysis of the cause of prolonged PT.