Comparison of assessment of coagulation in healthy dogs by the TEG 6s and TEG 5000 viscoelastic analyzers

Abstract

The TEG 6s (Haemonetics) point-of-care viscoelastic analyzer is portable, compact, simple to use, and has the potential for rapid viscoelastic analysis that can guide the treatment of veterinary patients at the site of care. Although approved for use in people, the TEG 6s has yet to be evaluated for hemostatic analysis in veterinary medicine. Citrated whole blood (CWB) was collected from 27 healthy dogs. An aliquot of CWB from each dog was diluted by 33% with an isotonic crystalloid, representing an in vitro model of hemodilution. Unaltered and diluted CWB samples were analyzed using 2 TEG 6s and 6 TEG 5000 (Haemonetics) analyzers. The 6 TEG 5000 analyzers ran duplicate analyses of either unaltered or diluted samples using 1 of 3 reagents (Haemonetics): Kaolin TEG, RapidTEG, or TEG Functional Fibrinogen. Duplicate TEG 5000 analyses were averaged and compared with a single TEG 6s analysis. Lin concordance correlation coefficient and Bland-Altman plots were used to evaluate agreement of reaction time, kinetic time, alpha angle, maximum amplitude (MA), and G value (G) for samples activated with Kaolin TEG, and agreement of MA for samples activated with RapidTEG between the 2 machines. Overall, agreement between the TEG 6s and TEG 5000 analyzers was poor. Viscoelastic measurements by the TEG 6s and TEG 5000 in healthy dogs were not all interchangeable. Agreement was satisfactory only for MA and G measurements of diluted blood samples activated with Kaolin TEG, and MA measurements for both unaltered and diluted blood samples activated with RapidTEG.

Keywords: TEG 5000; TEG 6s; canine; coagulation; coagulopathy; thromboelastography; viscoelastic.

Figure 1.

Processing and TEG analysis of government-owned canine blood samples. A = alpha angle; G = G value; GOC = government-owned canine; K = kinetic time; MA = maximum amplitude; R = reaction time.

Figure 2.

Concordance plots of A. reaction time (min), B. kinetic time (min), C. maximum amplitude (mm), D. G value (d/sc), and E. alpha angle (degrees) for unaltered blood samples activated with Kaolin TEG, and F. maximum amplitude (mm) for unaltered blood samples activated with RapidTEG comparing the TEG 6s and TEG 5000 machines. CCC = Lin concordance correlation coefficient; LCI = lower bound of the 95% one-sided CI.

Figure 3.

Concordance plots of A. reaction time (min), B. kinetic time (min), C. maximum amplitude (mm), D. G value (d/sc), and E. alpha angle (degrees) for diluted blood samples activated with Kaolin TEG, and F. maximum amplitude (mm) for diluted blood samples activated with RapidTEG comparing the TEG 6s and TEG 5000 machines. CCC = Lin concordance correlation coefficient, LCI = lower bound of the 95% one-sided CI.