Monitoring patients with the lupus anticoagulant while treated with vitamin K antagonists: communication from the SSC of the ISTH.

Patients on vitamin K antagonists (VKA) need frequent dose-adjustment based on the prothrombin time (PT) test with results expressed as international normalized ratio (INR). The need for the INR stems from the evidence that PT results obtained with commercial thromboplastins are varied owing to their different sensitivity to the coagulation defect induced by VKA. Consequently, PT results obtained for the same patient cannot be compared across labs.This article is protected by copyright. All rights reserved.