Quality assurance and computerised decision support will help to minimise inconsistencies

Monitoring treatment with anticoagulants is traditionally done in hospital because it requires laboratory blood tests and expert interpretation of the test results. The growing pressure on general practices to undertake monitoring of warfarin treatment has therefore led to concerns over the lack of resources and expertise in primary care.1 The use of computerised decision support systems in general practices may help with dosing.2 Other problems remain, however, including questions about the reliability of the international normalised ratio, the validity of current reference ranges, and where the test should be performed.

The purpose of oral anticoagulant treatment is to decrease thrombotic episodes, particularly stroke, by interfering with the haemostatic pathways.3 The intensity of anticoagulant effect required for any particular indication remains controversial.4 There have been problems in standardising test results between different centres at local and international levels. Data showing wide international variation in mean warfarin doses—Hong Kong under 2 mg, North America over 8 mg, and British figures between these extremes5—led to international collaboration to improve testing and …