Performance of point-of-care international normalized ratio measurement to diagnose trauma-induced coagulopathy.

Background: Trauma-induced coagulopathy (TIC) is a common feature after severe trauma. Detection of TIC is based upon classic coagulation tests including international normalized ratio (INR) value. Point-of-care (POC) devices have been developed to rapidly measure INR at the bedside on whole blood. The aim of the study was to test the precision of the Coagucheck® XS Pro device for INR measurement at hospital admission after severe trauma.

Methods: We conducted a prospective observational study in a French level I trauma center. From January 2015 to May 2016, 98 patients with a suspicion of a post-traumatic acute hemorrhage had POC-INR measurement on whole blood concomitantly to classic laboratory INR determination (lab-INR) on plasma at hospital admission. The agreement between the two methods in sorting three predefined categories of INR (normal coagulation, moderate TIC and severe TIC) was evaluated using the Cohen's kappa test with a quadratic weighting. The correlation between POC-INR and lab-INR was measured using the Pearson's coefficient. We also performed a Bland and Altman analysis.

Results: The agreement between the lab-INR and the POC-INR was moderate (Kappa = 0.45 [95% CI 0.36-0.50]) and the correlation between the two measurements was also weak (Pearson's coefficient = 0.44 [95% CI 0.27-0.59]). Using a Bland and Altman analysis, the mean difference (bias) for INR was 0.22 [95% CI 0.02-0.42], and the standard deviation (precision) of the difference was 1.01.

Discussion/conclusion: POC Coagucheck® XS Pro device is not reliable to measure bedside INR. Its moderate agreement with lab-INR weakens the usefulness of such device after severe trauma.

Trial Registration: NCT02869737 . Registered 9 August 2016.