A NATIONAL FIELD STUDY OF QUALITY ASSESSMENT (QA) OF COAGUCHEK MONITORS
Abstract number: P-T-665
Meijer1 P., Kluft1 C., Poller2 L., van der Meer3 F.J.M., Keown2 M., Ibrahim2 S., van den Besselaar4 A.M.H.P., Tripodi5 A., Jespersen6 J.
11ECAT Office, ECAT Foundation, Leiden, Netherlands 22European Action on Anticoagulation, Central Facility, Faculty of Life Sciences, University of Manchester, Manchester, United Kingdom 33Thrombosis Service 44Department of Hematology, Haemostasis and Thrombosis Research Center, Leiden University Medical Center, Leiden, Netherlands 55A Bianchi Bonomi, Hemophilia & Thrombosis Centre, University of Milan, Milan, Italy 66Clinical Biochemistry, Institute for Thrombosis Research, Ribe County Hospital in Esbjerg, Esbjerg, Denmark
How-to-cite Meijer P, Kluft C, Poller L, van der Meer FJM, Keown M, Ibrahim S, van den Besselaar AMHP, Tripodi A, Jespersen J. A NATIONAL FIELD STUDY OF QUALITY ASSESSMENT (QA) OF COAGUCHEK MONITORS. J Thromb Haemost 2007; 5 Supplement 2: P-T-665
Abstract
Introduction: There has been no satisfactory QA provided for the CoaguChek monitor. ECAA developed an EC approved system.
523 patients brought their CoaguChek monitors for QA at Netherlands Thrombosis Centres.
Methods:Certified INR
Certified CoaguChek INR for the set of 5 ECAA QA plasmas were provided by Leiden, Manchester and Milan using a single lot of test strips.
Performance Criteria
15% deviation from certified INR on a single plasma was defined as the acceptable limit. Greater deviation with one or more of the 5 ECAA QA plasmas was "significant INR deviation".
Results: The 5 QA samples were tested on the same occasion on each of the 523 monitors. The table shows the number of monitors and percentages (in brackets) giving "significant INR deviation".
106 monitors (20.3%) exceeded 15% INR deviation with at least one plasma. 81 (76.4%) with one, 19 (17.9%) with two, five with 3 and one with 4 plasmas.
Differences in the performance of lots of test strips were also seen (see separate abstract).
Table:
| Plasmas | Certified CoaguChek INR (SD) | 15% or more Deviation | Mean INR All Monitors (SD) |
|---|
| QC1 | 1.76 (0.12) | 6 (1.1) | 1.76 (0.13) |
| QC2 | 2.65 (0.12) | 42 (8.0) | 2.53 (0.23) |
| QC3 | 2.86 (0.21) | 32 (6.1) | 2.93 (0.31) |
| QC4 | 3.70 (0.38) | 17 (3.3) | 3.61 (0.25) |
| QC5 | 4.41 (0.21) | 41 (7.8) | 4.31 (0.44) |
| Total | – | 138 (5.3) | 3.03 (0.93) |
Conclusions: The feasibility of rapid large scale QA of individual CoaguCheks with the ECAA plasma sets is shown.
INR discrepancies were however not due simply to instrument variability but also to inter-lot variation of CoaguChek test strips.
CoaguChek uses whole blood but previous ECAA studies have shown that the combination of plasma and calcium chloride in the ECAA procedure closely parallels whole blood in ISI calibration and INR certification.
