R Zenlander1, M von Euler2,3,4, J Antovic1,5, A Berglund3,6. 1. Department of Clinical Chemistry, Karolinska University Hospital, Stockholm, Sweden. 2. Department of Clinical Pharmacology, Karolinska University Hospital, Stockholm, Sweden. 3. Department of Clinical Science and Education, Karolinska Institutet, Stockholm, Sweden. 4. Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden. 5. Department of Coagulation Research, Institute for Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden. 6. Department of Internal Medicine, Section of Neurology, Södersjukhuset, Stockholm, Sweden.
Abstract
OBJECTIVES: Effective anticoagulant therapy is a contraindication to thrombolysis, which is an effective treatment of ischemic stroke if given within 4.5 hours of symptom onset. INR above 1.7 is generally considered a contraindication for thrombolysis. Rapid measurement of INR in warfarin-treated patients is therefore of major importance in order to be able to decide on thrombolysis or not. We asked whether INR measured on a point-of-care instrument would be as good as a central laboratory instrument. MATERIAL AND METHODS: A total of 529 consecutive patients who arrived at the emergency department at a large urban teaching hospital with stroke symptoms were enrolled in the study. INR was measured with a CoaguChek and a Sysmex instrument. Basic clinical information such as age, sex, and diagnosis (if available) was recorded. INR from the instruments was compared using linear regression and Bland-Altman plot. RESULTS: Of 529 patients, 459 had INR results from both instruments. Among these, 3 patients were excluded as outliers. The rest (n = 456) showed good correlation between the methods (R2 = 0.97). In the current setting, CoaguChek was in median 63 minutes faster than Sysmex. CONCLUSION: Our results indicate that point-of-care testing is a safe mean to rapidly acquire a patient's INR value in acute clinical situations.
OBJECTIVES: Effective anticoagulant therapy is a contraindication to thrombolysis, which is an effective treatment of ischemic stroke if given within 4.5 hours of symptom onset. INR above 1.7 is generally considered a contraindication for thrombolysis. Rapid measurement of INR in warfarin-treated patients is therefore of major importance in order to be able to decide on thrombolysis or not. We asked whether INR measured on a point-of-care instrument would be as good as a central laboratory instrument. MATERIAL AND METHODS: A total of 529 consecutive patients who arrived at the emergency department at a large urban teaching hospital with stroke symptoms were enrolled in the study. INR was measured with a CoaguChek and a Sysmex instrument. Basic clinical information such as age, sex, and diagnosis (if available) was recorded. INR from the instruments was compared using linear regression and Bland-Altman plot. RESULTS: Of 529 patients, 459 had INR results from both instruments. Among these, 3 patients were excluded as outliers. The rest (n = 456) showed good correlation between the methods (R2 = 0.97). In the current setting, CoaguChek was in median 63 minutes faster than Sysmex. CONCLUSION: Our results indicate that point-of-care testing is a safe mean to rapidly acquire a patient's INR value in acute clinical situations.