Blood coagulation in the spotlight

The annual scientific meeting run by UK NEQAS (National External Quality Assessment Service) for Blood Coagulation (BC) is a prestigious event that attracts internationally recognised experts to present state-of-the-art reviews on clinical, laboratory and research aspects of haemostasis. In addition to the formal lecture programme of the meeting, a significant commercial exhibition offered delegates the opportunity to view the most up-to-date analytical, diagnostic and therapeutic innovations in the field of haemostasis.

Oral anticoagulation

Professor Isobel Walker UK NEQAS BC scheme director, opened the meeting, welcomed delegates and thanked the speakers and exhibitors, before introducing Dr Mike Makris (Sheffield) to chair the opening session, which focused on venous thrombosis and oral anticoagulation. The first presentation entitled Anticoagulant Dosing – Do We All Agree? was given by Dr Ian Jennings (Sheffield). Dose-adjusted therapy with vitamin K antagonists (e.g. warfarin), according to the international normalised ratio (INR), is an effective and wellestablished practice for the treatment and prevention of venous thromboembolism (VTE). While many quality assessment schemes are available to monitor the accuracy and precision of the INR result, there is no established system to assess the quality of anticoagulation management and its variation between different centres or individuals. UK NEQAS attempted to address this by providing participating centres with relevant clinical details and historical INR and dose data for four hypothetical cases. Using these data, together with a given current INR, participants were asked to suggest the appropriate target INR, dose and retest interval for each case. Case one was considered very straightforward with the previous INRs being stable and in range, the previous doses unchanged and the current INR also in range. Not surprisingly, there was good agreement, with 99% of respondents suggesting the same dose and similar recall interval. The other three cases were less straightforward and showed varying degrees of INR fluctuation, dose variation and changing clinical background. In each of these cases, respondents suggested significantly different target INR, dose and recall interval. The exercise illustrated that, given similar clinical situations, there are large and potentially clinically significant differences in the approach to managing oral anticoagulation other than when the dose is stable and the INRs are stable and in range.