American journal of clinical pathology
-
Am. J. Clin. Pathol. · Jul 2008
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. ⋯ 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.
-
Am. J. Clin. Pathol. · Jul 2008
Comparative StudyParameters of thromboelastography in healthy newborns.
Thromboelastography (TEG) aids in monitoring a patient's global hemostatic system by measuring the rate of clot formation, clot strength, and stability. The usefulness of TEG in pediatric settings, especially with neonates, is limited owing to a lack of neonatal reference values. In this study, neonatal TEG reference intervals were developed and results correlated with other coagulation test parameters. ⋯ Neonatal TEG reaction time (time clot formation begins), clot firmness (shear elastic modulus strength), and platelet function analysis closure times were significantly lower than those in adult ranges (P< .001). When compared with the values for children, TEG reaction time, angle, coagulation index, clot firmness value, and clot kinetics (time from clot formation to time amplitude reaches 20 mm) were significantly different (P< .001) among neonates. TEG can be used to interpret the data for newborns by using reference values obtained in the present study.
-
Am. J. Clin. Pathol. · Jul 2008
Comparative StudyComparison of emergency department patient classification by point-of-care and central laboratory methods for cardiac troponin I.
For patients admitted to the emergency department (ED) with suspected acute coronary syndrome, we compared results of a rapid, point-of-care whole blood assay for cardiac troponin I (Abbott i-STAT, Abbott Point-of-Care, East Windsor, NJ) (Tn-P) with an automated central laboratory plasma assay (Siemens TnI-Ultra, Siemens Medical Solutions Diagnostics, Tarrytown, NY) (Tn-U). Clinical data were obtained during a 6-month period during which ED patients were screened by Tn-P, with retesting of elevated results by Tn-U. ⋯ Of the negatives, 5.8% retested as elevated by Tn-U, but with levels no higher than 0.1 ng/mL (0.1 microg/L). Rapid whole blood testing for cardiac troponin I gave generally reliable patient classifications compared with plasma testing in the central laboratory, but besides missing small elevations, produced some apparent false-positives.