This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hematology, Subject name: Pharmacology
aPTT is done for assessing? 
Select and explain. 
A. Warfarin toxicity, B. LMW heparin, C. Heparin toxicity, D. Extrinsic coagulation pathway defect
C: Heparin toxicity
Answer: C: Heparin toxicity 
Explanation: Ref: KD Tripathi, 7th ed. P 618-620PT (Prothrombin Time)aPTT (Activated Partial Thromboplastin Time)* Assess activity of extrinsic coagulation pathway.* Used when on warfarin treatment.* WePT: Warfarin for extrinsic; PT value assessed.* Assess activity of intrinsic coagulation pathway.* Used while on heparin treatment.* HINT: Heparin for intrinsic; aPTT value assessed.