Operator-based variability of equine thromboelastography.
Abstract: To determine the extent of intraoperator (between duplicate samples) and interoperator (between different operators) variability in equine thromboelastography (TEG). Methods: 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). Methods: Twenty hospitalized adult horses with no clinical evidence of systemic inflammation. 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.
© Veterinary Emergency and Critical Care Society 2017.
Publication Date: 2017-05-18 PubMed ID: 28520166DOI: 10.1111/vec.12610Google Scholar: Lookup
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- Journal Article
- Adult Horses
- Blood
- Blood Analysis
- Clinical Findings
- Clinical Pathology
- Clinical Study
- Coagulation
- Comparative Study
- Diagnosis
- Diagnostic Technique
- Disease Diagnosis
- Equine Diseases
- Equine Health
- Hemostasis
- Hospitalization
- In Vivo
- Intra-Articular Injection
- Laboratory Methods
- Physiology
- Veterinary Medicine
- Veterinary Research
Summary
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The research article investigates the variability in equine thromboelastography (TEG), a blood test used to assess coagulation status, across duplicate samples and different operators. The study reveals that some measurements related to clot characteristics are more reliably reproduced across different tests and operators than others.
Research Methodology
- Two sets of operators (A/B and A/C) carried out TEG tests on two samples from each of the 20 horses that were part of the study.
- Each test measured specific clotting parameters including clot initiation time (R), clot formation time (K), rate of clot formation (α), clot strength (MA), and viscoelastic/shear strength (G).
- The samples for the test were collected using vacuum-assisted blood collection within 30-45 minutes prior to the test.
- The operators then independently evaluated the clinical coagulation status for each sample.
- The study relied on coefficients of variation (CV), descriptive statistics, and paired sample t-tests or Wilcoxon matched pair signed-rank test to compare the variability in results both within and between operators.
Results and Findings
- The study found that the intraoperator CVs ranged from 2.6% to 18%. This implies that the results obtained by a single operator on duplicate samples from a horse were reasonably consistent but did have some variation.
- The clot strength (MA) and viscoelastic/shear strength (G) showed low variability both within a single operator’s tests as well as across different operators. This means that these measurements are more reliable and reproducible.
- On the other hand, clot formation time (K) showed the highest level of variability, implying that this measurement is less reliably reproduced across different tests.
- Overall, intraoperator variability was found to be lower than interoperator variability for all TEG parameters.
- 70% of the horses had at least one TEG variable outside the established reference intervals, suggesting that these results may not always align with predetermined standard ranges.
- The assessment of coagulation status remained fairly consistent between different operators, indicating good interoperator agreement in interpreting the test results.
Conclusions
- The study concluded that while there is some variability in TEG measurements both within individual operators and between different operators, certain readings such as MA and G provide more consistent and reliable measures of coagulation status.
- The greatest variability was observed in the early phase of clot formation. Therefore, additional research may be beneficial to improve the reliability of this parameter.
Cite This Article
APA
Thane K, Bedenice D, Pacheco A.
(2017).
Operator-based variability of equine thromboelastography.
J Vet Emerg Crit Care (San Antonio), 27(4), 419-424.
https://doi.org/10.1111/vec.12610 Publication
Researcher Affiliations
- Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA, 01536.
- Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA, 01536.
- Department of Clinical Sciences, Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA, 01536.
- Dr.'s Pacheco current address: Genesee Valley Equine Clinic, Scottsville, NY.
MeSH Terms
- Animals
- Blood Coagulation / physiology
- Blood Coagulation Tests / veterinary
- Female
- Horses / blood
- Observer Variation
- Reference Values
- Thrombelastography / standards
- Thrombelastography / veterinary
Citations
This article has been cited 4 times.- York W, Smith MR, Liu CC. Use of Citrated Whole Blood for Point-of-Care Viscoelastic Coagulation Testing in Dogs. Front Vet Sci 2022;9:827350.
- Balandina AN, Serebriyskiy II, Poletaev AV, Polokhov DM, Gracheva MA, Koltsova EM, Vardanyan DM, Taranenko IA, Krylov AY, Urnova ES, Lobastov KV, Chernyakov AV, Shulutko EM, Momot AP, Shulutko AM, Ataullakhanov FI. Thrombodynamics-A new global hemostasis assay for heparin monitoring in patients under the anticoagulant treatment. PLoS One 2018;13(6):e0199900.
- Vokes JR, Lovett AL, de Kantzow MC, Rogers CW, Wilkins PA, Sykes BW. Comparison of Citrated Whole Blood to Native Whole Blood for Coagulation Testing Using the Viscoelastic Coagulation Monitor (VCM Vet™) in Horses. Animals (Basel) 2024 Oct 8;14(19).
- Lovett AL, Gilliam LL, Sykes BW, McFarlane D. Thromboelastography in obese horses with insulin dysregulation compared to healthy controls. J Vet Intern Med 2022 May;36(3):1131-1138.
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