Point-of-care International Normalised Ratios: UK NEQAS experience demonstrates necessity for proficiency testing of three different monitors

Abstract

External quality assessment (EQA) or proficiency testing is widely considered to be necessary for International Normalised Ratio (INR) determinations performed in conventional laboratory settings. There is increasing use of near-patient-test (NPT) or point-of-care (POC) INR devices and it is not known whether EQA is also necessary for these monitors. We report here on six years experience of proficiency testing for POC monitors used by health care professionals. Three devices were used by >10 centres who participated in the programme, the CoaguChek (CUC), the CUC-S and the TAS or Rapidpoint Coag. Not all users of the same type of monitor obtained the same INR result when analysing the same plasma sample. For the three monitors the CV of results in different centres was 11-14%. The variation between results in different centres could relate to inappropriately handled proficiency testing material, inaccuracies in the calibration of the system by the manufacturer or deterioration during transport/storage of the test strips. In each survey 10-11% of centres using POC monitors obtained INR results which were >15% different from those in other centres using the same monitors. For hospital laboratories using conventional INR techniques this figure was 12%. The relationship between INR results obtained by users of the Rapidpoint Coag or TAS monitor and results obtained by conventional techniques was not constant over the period of study. During one period INRs with TAS were 13.7% greater than with conventional methods. For the remaining three time periods results were similar. Our data suggest that the variation between INR results determined with three POC monitors show similar variation to that observed in hospital laboratories using conventional methods. Based on our data we recommend that users of these POC monitors participate regularly in an independent external proficiency testing programme.

Quality Assessment of CoaguChek Point-of-Care International Normalized Ratio Monitors: A Note of Caution

“…We recently reported results for 6 years (1996 -2002) of experience with external QA (EQA) of CUC and CUC-S devices, comparing Ͼ30 test samples analyzed by up to 175 centers (2 ). We have continued to perform EQA surveys and recently analyzed data on 8 different freeze-dried plasmas obtained in 2006 from Ͼ800 centers, grouping results according to the lot number of test strips used for analysis.…”

External quality assessment of point-of-care International Normalized Ratio (INR) testing in Europe

“…The United Kingdom National External Quality Assessment Service (UKNEQAS) has reported their experience with EQAS for POCT INR over a 6-year period, and stated that this kind of control is both possible and necessary for health care professionals to obtain good analytical quality (14).…”

“…Publications show that an EQAS for POCT INR is available in the Czech Republic (15), the Netherlands (16), Norway (17) and the UK (14). To our knowledge, however, no studies have investigated the coverage of POCT INR schemes in Europe.…”

Telemedicine For Managing Patients on Oral Anticoagulant Therapy

“…The choice of this cut-off value derived from the fact that a higher value would require remarkable adjustments in the therapeutic regimen.  External quality assessment (NEQAS): it considers both laboratory data and clinical treatment, to assess the accuracy of the global therapeutic management (Kitchen et al, 2006).…”