TitleOperator-based variability of equine thromboelastography.
Publication TypeJournal Article
Year of Publication2017
AuthorsThane, K, Bedenice, D, Pacheco, AP
JournalJ Vet Emerg Crit Care (San Antonio)
Date Published2017 Jul
KeywordsAnimals, Blood Coagulation, Blood Coagulation Tests, Female, Horses, Observer Variation, Reference Values, Thrombelastography

OBJECTIVE: To determine the extent of intraoperator (between duplicate samples) and interoperator (between different operators) variability in equine thromboelastography (TEG).

DESIGN: Kaolin-activated TEG was performed in duplicate by operator-pair A/B or A/C (2 groups of 10 horses) using discrete setups, within 30-45 minutes of vacuum-assisted blood collection. Recorded TEG variables included clot initiation time (R), clot formation time (K), rate of clot formation (α), clot strength (MA), and viscoelastic/shear strength (G). Operators independently determined the clinical coagulation status for each sample. Intra- and interoperator variabilities were reported as coefficients of variation (CV), using descriptive statistics and paired samples t-test or Wilcoxon matched pair signed-rank test (P < 0.05 considered significant).

ANIMALS: Twenty hospitalized adult horses with no clinical evidence of systemic inflammation.

MEASUREMENTS AND MAIN RESULTS: Mean intraoperator CVs ranged from 2.6 to 14% (operator A), 2.8 to 13% (operator B) and 1.2 to 18% (operator C). Both intra- and interoperator variabilities were lowest for MA (1.2-3.2%) and G (2.9-7.3%), and highest for K (13-23%). Mean CVs for all TEG parameters were lower when comparing intra- to interoperator variation. Seventy percent of horses had at least 1 TEG variable (out of 4 replicates) outside the established reference intervals. Assessment of coagulation status was conserved between operators in 9/10 and 8/10 horses for A/B and A/C, respectively, with comparable agreement between operator A/B (к = 0.73) and A/C (к = 0.74).

CONCLUSIONS: TEG measurements of MA and G are more reproducible than assessment of K, within samples and between operators. The highest test variability was thus observed within the early phase of clot formation.

Alternate JournalJ Vet Emerg Crit Care (San Antonio)
PubMed ID28520166