Precision and accuracy of point‐of‐care testing coagulometers used for self‐testing and self‐management of oral anticoagulation therapy

Abstract

To cite this article: Christensen TD, Larsen TB. Precision and accuracy of point-of-care coagulometers used for self-testing and self-management of oral anticoagulation therapy. J Thromb Haemost 2012; 10: 251-60.Summary. Background: Oral anticoagulation therapy is monitored by the use of the International Normalized Ratio (INR). Patients who perform self-testing or self-management use a point-of-care testing (POCT) coagulometer (INR monitor) to estimate their INRs. A precondition for a correct dosage of coumarins is a correct INR estimation, and the method and apparatus used for providing the INR measurements are crucial in this context. Several studies have been published regarding the precision and accuracy of these POCT coagulometers, and have led to diverse conclusions. It is difficult and challenging to perform an overview of the literature, owing to the vast amount of papers, with differences in design, statistical analysis, etc. Objectives: The aim of this systematic review was to analyze the current literature, especially regarding the precision and accuracy of the POCT coagulometers, to provide recommendations for clinical use and quality control, and to point out areas for future research. Methods: We included a total of 22 studies, of which four were characterized as high-quality studies. Results: The precision of the POCT coagulometers was generally adequate for clinical use. Their performance in terms of accuracy has to be viewed in the context of the inherent inaccuracies of INR measurements. Conclusions: The accuracy of POCT coagulometers seems, in this respect, to be generally acceptable, and they can be used in a clinical setting.

Efficacy of Point-of-Care Testing (POCT) in Reducing Total Waiting Time at Warfarin Clinic of a District Hospital: A Cohort Study

“…A recent systematic review on the precision and accuracy of POC coagulometers reviewed the evidence for CoaguChek XS, INRatio, and ProTime/ProTime 3 [12]. Across 14 studies on the accuracy of CoaguChek, the correlation coefficient varied from 0.81 to 0.95 [5].…”

The clinical effectiveness and cost-effectiveness of point-of-care tests (CoaguChek system, INRatio2 PT/INR monitor and ProTime Microcoagulation system) for the self-monitoring of the coagulation status of people receiving long-term vitamin K antagonist therapy, compared with standard UK practice: systematic review and economic evaluation

“…Normally, the precision or reproducibility of point-of-care devices is expressed by means of the coefficient of variation (CV) of the variability, while the accuracy is the level of agreement between the result of one measurement and the true value and is expressed as correlation coefficient. 35 41 Similarly, the international guidelines prepared in 2005 by the International Self-Monitoring Association for oral Anticoagulation stated that 'Point-of-care instruments have been tested in a number of different clinical settings and their accuracy and precision are considered to be more than adequate for the monitoring of OAT in both adults and children' (p. 40). 42 …”

Application of a Simulation Model to Estimate Treatment Error and Clinical Risk Derived from Point-of-Care International Normalized Ratio Device Analytic Performance

“…In 2007, ISO 17593 performance expectations for POCT INR devices at INR values <2 were that 90% of results must fall within ±0.5, and for INR values from 2 to 4.5, the expectation was ±30% (8). In 2012, Christensen and Larsen (18) published a systematic review of the literature that examined the analytical performance (i.e., accuracy and precision) of several POCT INR devices in an effort to provide performance expectations for clinical use. According to this study, an ideal level of imprecision would be <3%, while an ideal analytical accuracy was proposed to be ±0.2 INR within the therapeutic range (i.e., 2-3 INR).…”