Despite limitations, overall evidence shows that point of care testing is reliable

The development and adoption of instruments for determining the international normalised ratio (INR) at the point of care for monitoring treatment with coumarin anticoagulants has added another variable to the question of the precision of INR measurements. In this issue Poller et al (p 30) show discrepancies between results when two such instruments are used and the best estimate of the true INR.1 These observations, however, should be seen in the context of the already recognised limitations of the INR system and the potential for using point of care testing to deliver safe and effective anticoagulant therapy efficiently.

Coumarin anticoagulants remain the preferred method of prophylaxis and treatment for thrombosis in a range of clinical situations. Around 1% of the populations of many countries receive such treatment, a proportion boosted by the increasing use of oral anticoagulation as thromboprophylaxis in atrial fibrillation.2 Monitoring of the anticoagulant effect of coumarins, however, is essential, and the prothrombin time is used for this …