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)
Volume27
Issue4
Pagination419-424
Date Published2017 Jul
ISSN1476-4431
KeywordsAnimals, Blood Coagulation, Blood Coagulation Tests, Female, Horses, Observer Variation, Reference Values, Thrombelastography
Abstract

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.

DOI10.1111/vec.12610
Alternate JournalJ Vet Emerg Crit Care (San Antonio)
PubMed ID28520166