The two methods were compared using Pearson correlation test and Deming linear regression analysis using GraphPad Prism® software. Bias versus the reference method was also calculated. Repeatability was assessed on 102 pairs of capillary blood samples. Coefficient of variation (%CV) was calculated across four INR ranges : 1-2; 2-3, 3-4 and >4. In addition, normal values were verified on 30 healthy donors and reported as percentile 2.5% and 97.5%. Results INRs measured with the Xprecia stride correlated strongly with the results obtained with our laboratory reference method, with a Pearson coefficient of 0.92. The Deming regression analysis yielded a slope of 1.15 (95% confidence interval: 1.07 – 1.22) and an intercept of -0.37 (95% CI: -0.54 - -0.19), demonstrating a slight systematic proportional bias. The absolute difference in INR measurements between the two methods was 0.03 units, the results obtained with the Xprecia stride being overall 1.5% lower. Across INR ranges, the minimum bias was -0.10 for INR 1-2 and the maximum bias was +0.43 for INR >4. Repeatability study showed that the mean CV was 3.6%, with the lowest CV = 2.7% for INR range 2-3 and highest CV = 5.5% for INR 3-4. These results fulfilled the desirable specifications published by the French society of Thrombosis and Hemostasis, that is a CV < 5.3% for INR 1-2 and < 7.5% for INR > 2. The expected normal values, as determined by the manufacturer, were 0.9 – 1.1. These reference values were verified on 30 healthy subjects: the INR ranged from 0.9 to 1.3. Although the upper limit of the interval was slightly higher, the reference range was nearly identical to that expected. Conclusions Overall, INR testing with the Xprecia Stride coagulation analyzer showed strong correlation with the laboratory automated reference method and good analytical performances in term of repeatability. These results confirm that the Xprecia Stride may be used at the point of care for reliable INR measurements. Category: Clinical & Laboratory
The two methods were compared using Pearson correlation test and Deming linear regression analysis using GraphPad Prism® software. Bias versus the reference method was also calculated. Repeatability was assessed on 102 pairs of capillary blood samples. Coefficient of variation (%CV) was calculated across four INR ranges : 1-2; 2-3, 3-4 and >4. In addition, normal values were verified on 30 healthy donors and reported as percentile 2.5% and 97.5%. Results INRs measured with the Xprecia stride correlated strongly with the results obtained with our laboratory reference method, with a Pearson coefficient of 0.92. The Deming regression analysis yielded a slope of 1.15 (95% confidence interval: 1.07 – 1.22) and an intercept of -0.37 (95% CI: -0.54 - -0.19), demonstrating a slight systematic proportional bias. The absolute difference in INR measurements between the two methods was 0.03 units, the results obtained with the Xprecia stride being overall 1.5% lower. Across INR ranges, the minimum bias was -0.10 for INR 1-2 and the maximum bias was +0.43 for INR >4. Repeatability study showed that the mean CV was 3.6%, with the lowest CV = 2.7% for INR range 2-3 and highest CV = 5.5% for INR 3-4. These results fulfilled the desirable specifications published by the French society of Thrombosis and Hemostasis, that is a CV < 5.3% for INR 1-2 and < 7.5% for INR > 2. The expected normal values, as determined by the manufacturer, were 0.9 – 1.1. These reference values were verified on 30 healthy subjects: the INR ranged from 0.9 to 1.3. Although the upper limit of the interval was slightly higher, the reference range was nearly identical to that expected. Conclusions Overall, INR testing with the Xprecia Stride coagulation analyzer showed strong correlation with the laboratory automated reference method and good analytical performances in term of repeatability. These results confirm that the Xprecia Stride may be used at the point of care for reliable INR measurements. Category: Clinical & Laboratory
abstract%20XPrecia%20BSTH%202016%20vf.docx