Reliability of CoaguChek Pro II Point of Care System in Outpatient Setting in Farwaniya Hospital, Kuwait

Abstract

Point of care testing (POCT) coagulometers are widely used for international normalized ratio (INR) monitoring for patients on vitamin K antagonists (VKA) therapy. In our study, we investigated the accuracy and reliability of CoaguChek pro II (Roche Diagnostics) as an alternative for standard laboratory testing (SLT) by ACL TOP 500 top system in outpatient department setting. Methods: We enrolled a total of 174 INR results in our study which were measured by CoaguChek ProII and ACL TOP 500 top. The three arms of the study were: INR <3.5, 3.5-4.4, and ≥4.5. The results were compared using Passing Bablok regression analysis and Bland-Altman plot. The agreement between the two methods was further evaluated to demonstrate the impact on dosing decision. Furthermore, the degree of patient satisfaction with POCT in our INR clinic was assessed by participating in a survey. Results: The overall correlation of INR measurements between POCT and SLT in our study was strong (r = 0.95), however, the correlation between the two methods in the 3.5-4.4 arm was moderate (r = 0.502). The overall agreement between the two methods in all three arms of the study in terms of dosing decision was good (Kappa = 0.862), with only 12.6% of INR measurements showing a difference in dosing decision. Ninety-Seven percent of all INR values measured by CoaguChek Pro II within therapeutic range (INR<3.5) were within 0.5 INR units when compared to ACL TOP 500 Top. Furthermore, we concluded that more than 90% of the patients in our center were satisfied with the POC service. Conclusion: We concluded that POCT is a good alternative to SLT in INR values falling in therapeutic and supra-therapeutic ranges; however, additional comparative studies investigating the accuracy and reliability between the two methods for INR results between 3.5-4.4 will add to the current body of knowledge. Furthermore, the majority of patients were satisfied with the service provided in the POC INR clinic.