Oral anticoagulant therapy is monitored by
[A] APTT
([B] INR
[C] Factor X assay
[D] All three are needed
Answer = [B] INR (Ref: Katzung-Basic and Clinical Pharmacology 12th Edition)
The therapeutic range of oral anticoagulant therapy is defined in terms of INR ie international normalized ratio. Oral anticoagulants (eg Warfarin) are administered in doses that produce a target INR of 2.0-3.0 in most of the indications.
Anticoagulant Monitoring