Comparison of Point of Care INR Testing to Routine Coagulometric Method
Abstract
Aim: Point Of Care (POC) tests are quick tests that shorten the treatment period and are portable devices, which are easy to use for non-laboratory personnel. In this study we aimed to compare the results of INR (International Normalized Ratio) that were studied with POC testing using fingertip capillary blood and studied with coagulometric method using simultaneous venous blood in patients receiving anticoagulants.
Materials and methods: Two hundred and fifty outpatients (129 women and 121 men) using oral anticoagulant (OAC) drugs or monitoring for INR during preoperative preparation were included in this study. One hundred and three patients were using vitamin K antagonists (VKA) (%41,2). Approximately 10 μl of capillary blood collected from the fingertips of the patients were studied directly on the point of care test device (hemosense-inverness medical®), using electrochemical method. For the coagulometric method, approximately 2 ml blood samples were taken into a vacutainer tube containing sodium citrate. After centrifugation of the samples, tissue thromboplastin (TriniClot PT Excel S) was added, Prothrombin Time (PT) and INR analysis were performed with Coag A-MTX II-Trinity Biotech device. Daily controls of the device were performed before the study and samples were studied after obtaining the results in the expected range.
Results: INR measurements of venous and capillary blood samples of 250 patients were performed concurrently. The results were compared by linear regression analysis and a high correlation was found between the two methods (r=0.878). There were no significant difference between the genders. In the study, there was a good correlation in those with INR values below 2, and a high correlation in those with 2 and above.Conlusion:The POC method is a promising inexpensive method to meet the needs of clinicians in terms of regulating the treatment of patients requiring immediate outcomes and rapidly assessing the risk of bleeding, when a quality control program is implemented in accordance with the manufacturer's recommendations.