European Concerted Action on Anticoagulation (ECAA): International Normalized Ratio Variability of CoaguChek and TAS Point-of-Care Testing Whole Blood Prothrombin Time Monitors

L. Poller; M. Keown; N. Chauhan; C. Shiach; A. M. H. P. van den Besselaar; A. Tripodi; J. Jespersen

doi:10.1055/s-0037-1613345

Thrombosis and Haemostasis, Table of Contents

Thromb Haemost 2002; 88(06): 992-995
DOI: 10.1055/s-0037-1613345

Involvement of Thrombin Receptors in the Subject-dependent Variability in Ca2+ Signal Generation

Schattauer GmbH

European Concerted Action on Anticoagulation (ECAA): International Normalized Ratio Variability of CoaguChek and TAS Point-of-Care Testing Whole Blood Prothrombin Time Monitors

L. Poller^*

¹ECAA Central Facility, School of Biological Sciences, The University of Manchester, Manchester, UK

,

M. Keown

¹ECAA Central Facility, School of Biological Sciences, The University of Manchester, Manchester, UK

,

N. Chauhan

¹ECAA Central Facility, School of Biological Sciences, The University of Manchester, Manchester, UK

,

C. Shiach^*

²Department of Haematology, Manchester Royal Infirmary, Oxford Road, Manchester, UK

,

A. M. H. P. van den Besselaar^*

³Haemostasis and Thrombosis Research Centre, Leiden University Medical Center, Leiden, The Netherlands

,

A. Tripodi^*

⁴A Bianchi Bonomi, Haemophilia and Thrombosis Centre, IRCCS Maggiore Hospital, University of Milan, Milan, Italy

,

J. Jespersen^*

⁵Department for Thrombosis Research, University of Southern Denmark and Department of Clinical Biochemistry, Ribe County Hospital, Esbjerg, Denmark

› Author Affiliations

Abstract

Summary

The object was to assess the variability in displayed International Normalised Ratio (INR) between monitors of the same manufacture using whole blood samples from the same subjects. Two brands of monitor, CoaguChek Mini and the TAS PT-NC were tested.

14 instruments of each brand were tested on the same day at the same laboratory by the same operator using identical blood samples to avoid between-centre differences in samples and operator technique. Whole blood samples from two normal donors and four coumarintreated patients were tested to assess between-instrument variability of INR.

Results have been coded. There was a much wider dispersion of INR on Brand B than on Brand A. One Brand A instrument failed to give a result with one of the two whole blood samples from one patient. One Brand B monitor gave an aberrant result with one of the samples from a normal subject.

On both brands of monitor, INR variability appeared to be due mainly to duplication differences rather than between-instrument variability on both normal and coumarin whole blood samples.

Keywords

POCT monitors - prothrombin time - International Normalised Ratio - between-instrument variability - within-instrument variability

Full Text

References

References
1 Ansell J, Holden A, Knapic N. Patient self-management of oral anticoagulation guided by capillary (fingerstick) whole blood prothrombin times. Arch Intern Med 1989; 149: 2509-11.
2 White RH, McCurdy SA, von Marensdorft H, Woodruff DE, Leftgoff L. Home prothrombin time monitoring after initiation of warfarin therapy. Ann Intern Med 1989; 111: 730-7.
3 Leaning KE, Ansell JE. Advances in the monitoring of oral anticoagulation: Point-of-care testing, patient self-monitoring and patient self-management. J Thromb Thrombolysis 1996; 03: 377-83.
4 Kitchen S, Preston FE. Monitoring oral anticoagulant treatment with the TAS near-patient test system: comparison with conventional thromboplastins. J Clin Pathol 1997; 50: 951-6.
5 Gosselin R, Owings JT, White RH, Hutchinson R, Branch J, Mahackian K, Johnston M, Larkin EC. A comparison of Point-of-care instruments designed for monitoring oral anticoagulantion with standard laboratory methods. Thromb Haemost 2000; 83: 698-703.
6 Tripodi A, Arbini AA, Chantarangkul V, Bettega D, Mannucci PM. Are capillary whole blood coagulation monitors suitable for the control of oral anticoagulant treatment by the International Normalized Ratio?. Thromb Haemost 1993; 70: 921-4.
7 van den Besselaar AMHP. A Comparison of INRs Determined with a Whole Blood Prothrombin Time Device and two International Reference Preparations for Thromboplastin. Thromb Haemost 2000; 84: 410-2.
8 Poller L, Keown M, Chauhan N, van den Besselaar AMHP, Tripodi A, Jespersen J, Shiach C, Conard J, Dias D, Egberg N, Iriarte JA, Kontopoulou-Griva I, Otridge B. European Concerted Action on Anticoagulation (ECAA). Multicentre ISI calibration of two types of point-of-care prothrombin time monitor systems. Br J Haematol 2002; 116: 844-50.
9 Poller L, Keown M, Chauhan N, van den Besselaar AMHP, Meeuwisse-Braun J, Tripodi A, Clerici M, Jespersen J. European Concerted Action on Anticoagulation (ECAA). The use of plasma samples to derive International Sensitivity Index of whole blood Prothrombin Time Monitors. Clin Chem 2002; 48: 255-60.
10 Bland M. An introduction to medical statistics (third edition). Oxford: Oxford University Press; 2000. Ch 10: 177-9.
11 Poller L, Thomson JM, Taberner DA. Effect of automation on the prothrombin time test in NEQAS surveys. J Clin Pathol 1989; 42: 97-100.
12 Poller L, Thomson JM, Taberner DA, Clarke DK. The correction of coagulometers effects on international normalised ratios: a multicentre evaluation. Br J Haematol 1994; 84: 112-7.
13 Poller L, Triplett DA, Hirsh J, Carroll J, Clarke K. The Value of Plasmas Calibrants in Correcting Coagulometer Effects on International Normalized Ratios – An International Multicenter Study. Am J Clin Pathol 1995; 103: 358-65.
14 Poller L, van den Besselaar AMHP, Jespersen J, Tripodi A, Houghton D. The European Concerted Action on Anticoagulation (ECAA) Field studies of coagulometer effects on the ISI of ECAA thromboplastins. Thromb Haemost 1998; 80: 615-23.
15 D’Angelo A, Seveso MP, D’Angelo SV, Gilardoni F, Macagni A, Manotti C. Comparison of two automated coagulometers and the manual tilt tube method for the determination of prothrombin time. Am J Clin Pathol 1989; 92: 321-8.
16 Ray MJ, Smith IR. The dependence of the International Sensitivity Index on the coagulometer used to perform the prothrombin time. Thromb Haemost 1990; 63: 424-9.
17 van Rijn JLML, Schmidt ANico, Rutten W. Correction of instrument and reagent based differences in determination of the international normalised ratio (INR) for monitoring anticoagulant therapy. Clin Chem 1989; 355: 840-3.
18 Clarke K, Taberner DA, Thomson JM, Morris JA, Poller L. Assessment of value of calibrated lyophilized plasmas to determine International Sensitivity Index for coagulometers. J Clin Pathol 1992; 45: 58-60.