Normal reference intervals and the effects of sample handling on dynamic viscoelastic coagulometry (Sonoclot) in healthy adult horses: Dynamic viscoelastic coagulation in horses

OBJECTIVE: To determine reference intervals and the effect of sample agitation and rest time on Sonoclot analysis in healthy adult horses. DESIGN: Original prospective study. SETTING: University veterinary medical teaching hospital. ANIMALS: Sixty healthy adult horses. INTERVENTIONS: Blood was collected for assessment of complete blood count, serum biochemical analysis, and Sonoclot analysis. MEASUREMENTS AND MAIN RESULTS: Horses were determined to be healthy based upon physical examination, CBC, and serum biochemistry analysis. Blood was analyzed in a glass bead-containing cuvette using the Sienco Sonoclot analyzer following 2 rest periods (30 mins and 240 min) and with 2 sample handling interventions (agitated and nonagitated), to obtain values for clot rate, time-to-peak, activated clotting time, and platelet function. This study failed to detect a significant difference when a rest time of 30 minutes was compared with 240 minutes, but based on wide limits of agreement the 2 rest times were not considered interchangeable. Agitation at both rest times significantly affected all Sonoclot analyses leading to changes indicative of hypercoagulability. CONCLUSIONS: Sample agitation and rest time should be taken into consideration when developing preanalytical guidelines for Sonoclot analysis in horses. Calculated reference intervals were relatively wide. Further research is needed to evaluate the clinical utility of Sonoclot analysis in horses.