Comparison of native and citrated whole blood samples for rapid thromboelastography in Beagles

OBJECTIVE: To examine the extent to which rapid thromboelastography (r-TEG) could decrease the testing time in comparison with that required for kaolin-activated thromboelastography (TEG), and to compare 2 types of blood samples (ie, native and citrated whole blood [WB]), for determining r-TEG values in healthy dogs. DESIGN: Prospective observational study. SETTING: University teaching hospital. ANIMALS: Sixteen healthy Beagles. INTERVENTIONS: Kaolin-activated TEG test using citrated WB samples and r-TEG test using native and citrated WB samples were performed in 16 dogs. At 60 minutes after the initial blood sampling, further samples were collected from a subset of 6 dogs in the same manner to evaluate intraindividual repeatability of r-TEG. MEASUREMENTS AND MAIN RESULTS: The mean time to maximum amplitude (MA) for r-TEG with native and citrated WB samples was recorded as 1313.9 +/- 250.9 seconds and 1351.3 +/- 264.6 seconds (mean +/- SD), respectively, and 1779.9 +/- 197.0 seconds for kaolin-activated TEG. Coefficients of variation with native and citrated WB samples for r-TEG values, TEG-activated clotting time, clot formation time, alpha angle, and MA, were determined to be 13.4% versus 18.8%, 11.1% versus 16.6%, 4.2% versus 5.1%, and 10.0% versus 10.0%, respectively. Intraindividual variations were lower for native WB samples than for citrated WB samples. CONCLUSIONS: The r-TEG test significantly decreased the mean time to MA compared with the kaolin-activated TEG test. In addition, native WB samples showed lower coefficients of variation and intraindividual variation than citrated WB samples in r-TEG analysis; this suggests that native WB samples can provide more consistent results. Therefore, the r-TEG method using native WB samples is recommended for assessment of dogs' hemostatic status when an early diagnosis is required.