Reliability of international normalised ratios from two point of care test systems: comparison with conventional methods.
OBJECTIVE
To find out how accurately two point of care test systems--CoaguChek Mini and TAS PT-NC (RapidPointCoag)--display international normalised ratios (INRs).


METHODS
Comparison of the INRs from the two systems with a "true" INR on a conventional manual test from the same sample of blood.


METHODS
10 European Concerted Action on Anticoagulation centres.


METHODS
600 patients on long term dosage of warfarin.


METHODS
Comparable results between the different methods.


RESULTS
The mean displayed INR differed by 21.3% between the two point of care test monitoring systems. The INR on one system was 15.2% higher, on average, than the true INR, but on the other system the INR was 7.1% lower. The percentage difference between the mean displayed INR and the true INR at individual centres varied considerably with both systems.


CONCLUSIONS
Improved international sensitivity index calibration of point of care test monitors by their manufacturers is needed, and better methods of quality control of individual instruments by their users are also needed.
Poller
Leon
L
European Concerted Action on Anticoagulation Central Facility, School of Biological Sciences, University of Manchester, Manchester M13 9PT. ecaa@man.ac.uk
Keown
Michelle
M
Chauhan
Nikhil
N
van den Besselaar
Anton M H P
AM
Tripodi
Armando
A
Shiach
Caroline
C
Jespersen
Jorgen
J
D000925:Anticoagulants / Q000627:therapeutic use; D006801:Humans; D019934:International Normalized Ratio / Q000592:standards*; D019095:Point-of-Care Systems / Q000592:standards*; D012680:Sensitivity and Specificity; D014859:Warfarin / Q000627:therapeutic use
D000925:Anticoagulants; D014859:Warfarin