This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
The estimation of prothrombin level is useful in the following clotting factor deficiency , except 
Select and explain. 
A. 2, B. 5, C. 7, D. 9
D: 9
Answer: D: 9 
Explanation: ref Robbins 8/e p119;7/e p128;9/e p119 The PT test evaluates how well all of the coagulation factors in the extrinsic and common pathways of the coagulation cascade work together. Included are: factors I (Fibrinogen), II (Prothrombin), V, VII and X. The PT/INR may be done at the same time as a PTT, which evaluates the clotting factors that are pa of the intrinsic and common pathways: XII, XI, IX, VIII, X, V, II (prothrombin), and I (fibrinogen) as well as prekallikrein (PK) and high molecular weight kininogen (HK).