Accuracy of capillary whole blood international normalized ratio on the CoaguChek S, CoaguChek XS, and i-STAT 1 point-of-care analyzers.
We evaluated the accuracy of capillary whole blood international normalized ratio (INR) on the CoaguChek S (Roche Diagnostics, Indianapolis, IN), CoaguChek XS (Roche Diagnostics), and i-STAT 1 (i-STAT, East Windsor, NJ) point-of-care (POC) analyzers compared with venous plasma INRs determined by a reference laboratory method. Overall agreement between POC and laboratory plasma INR was very good, with median bias between capillary whole blood and laboratory plasma INRs varying from 0.0 to -0.2 INR units on all devices. More than 90% of results on the CoaguChek XS and i-STAT 1 and 88% of CoaguChek S results were within 0.4 INR units of the reference laboratory method. The CoaguChek XS and i-STAT 1 demonstrated greater accuracy than the CoaguChek S as measured by the number of results that differed by more than 0.5 INR units from the reference method. Median bias between CoaguChek S capillary whole blood and laboratory plasma INRs changed over time, demonstrating the need for ongoing quality assurance measures for POC INR programs.
Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
Brad S
BS
Karon
Robert D
RD
McBane
Rajeev
R
Chaudhry
Lisa K
LK
Beyer
Paula J
PJ
Santrach
D000925:Anticoagulants; D001777:Blood Coagulation; D002196:Capillaries; D016903:Drug Monitoring / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D019934:International Normalized Ratio / Q000592:standards*; D019095:Point-of-Care Systems / Q000592:standards*; D015203:Reproducibility of Results
D000925:Anticoagulants