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Question 302
Physiology → Haematology
Classification
Question
SSBAOptions
Explanation
low-molecular-weight heparin specifically acts on factor Xa and is not monitored through either APTT or PT. In contrast, APTT is described as being used to monitor the treatment effects of heparin.
Option Validity
A) Factor VII belongs to the extrinsic pathway assessed by PT. associates low-molecular-weight heparin with factor Xa rather than factor VII.
C) Factor XIII is involved in formation of a stable fibrin mesh and is not identified as the specific target of low-molecular-weight heparin. Bleeding time assesses platelet and vascular haemostasis.
D) does not define low-molecular-weight heparin by inhibition of platelet adhesion. Its stated specific coagulation target is factor Xa, and neither PT nor APTT is used for its monitoring.
E) Interference with vitamin K metabolism is the mechanism attributed to warfarin. It is not the mechanism given for low-molecular-weight heparin.
Further Reading
Saxena. Textbook for MRCOG-1. Physiology - Haematology - Activated Partial Thromboplastin Time, p.72.