Sonoclot coagulation analysis: A study of test variability

Objective: To test the reproducibility of Sonoclot coagulation analysis (SC A; Sienco Inc, Morrison, CO). The authors wished to determine if the mix/re lease of the preloaded celite activator in standard Sono-cuvettes could be responsible for the high variation coefficients for SCA parameters with cit rated whole blood and if citrated whole blood is optimal for SCA. Design: A prospective trial. Setting: A large academic teaching medical center. Participants: Eight healthy volunteers. Interventions: Repeated blood sampling was performed through indwelling rad ial artery catheters. Seven different Sonoclot analyzers were used to test seven different types of analysis procedures in the volunteers, involving a ctivators of different types and amounts and in different forms, and the us e of citrated or native whole blood. Measurements and Main Results: Two-way and one-way ANOVA, variance, varianc e analysis, and Tukey's test were used to evaluate differences in SCA metho ds and volunteer influence. A high variance, with SDs up to 200% of the med ian values of the SCA parameters with recalcified citrated blood and the st andard Sono-cuvette, was confirmed. SCA with native blood and/or the use of other types of preloaded activators, ie, kaolin, significantly (p < 0.05) reduced this variance. Repeated SCAs further reduced the variance to 10% to 35% of the variance for a single analysis (standard cuvette and native blo od). Conclusion: Improvement of the activator in the Sono-cuvette, use of native whole blood, and repeated Sonoclot analyses reduced the previously reporte d high variability of this instrument. Copyright (C) 1999 by W.B. Saunders Company.