Multicenter in vitro thromboelastography and thromboelastometry standardization.

Robert Goggs,Karl E Jandrey,Benjamin M Brainard,Armelle De Laforcade,Isabelle Goy‐Thollot,Antonio Borrelli,Annette Kutter,Benoît Rannou,Clara B Marschner,Daniel L Chan,Annemarie T Kristensen,Nadja Sigrist,Catherine Wagg

doi:10.1111/vec.12710

Abstract

To establish and compare the repeatability and reproducibility of activated thromboelastography (TEG) and thromboelastometry (ROTEM) assays. Multicenter in vitro test standardization. Veterinary academic centers. Test samples were obtained from normal, healthy dogs. Sixty identical 5mL aliquots of canine platelet-rich plasma collected by apheresis, frozen in 6% dimethyl sulfoxide, were tested initially. Sixty identical 6mL aliquots of canine fresh frozen plasma with admixed cryoprecipitate were subsequently evaluated. None. Frozen study samples, quality controls, reagents, and consumables were distributed to participating centers (7 TEG and 3 ROTEM). TEG centers analyzed study samples with kaolin and tissue factor activated assays; ROTEM centers ran proprietary ellagic acid activated and tissue factor activated assays. All machines underwent quality control prior to sample analysis. Within- and between-center coefficients of variation (CVs) were calculated and compared using Mann-Whitney tests and calculation of intraclass correlation coefficients. Within and between centers, individual parameters for both TEG and ROTEM assays were comparable. Both within-center and between-center CVs varied markedly (0.7-120.5% and 1.4-116.5%, respectively) with assay type, instrument, and parameter. CVs for equivalent parameters were not significantly different between the 2 platforms. Intraclass correlation coefficients suggested moderate agreement between centers. In general, individual parameter CVs for platelet-rich plasma samples were lower in TEG centers, while CVs for canine fresh frozen plasma with admixed cryoprecipitate samples were lower in ROTEM centers. More variation within and between centers was identified than anticipated, but some parameters such as alpha angle were repeatable and reproducible. Sample types for future multicenter standardization efforts will require further optimization and may need to be adapted separately to each platform. Individual centers using viscoelastic tests for evaluation and management of clinical patients should take steps to minimize preanalytical and analytical sources of variation.

Highlights

Patients with bleeding diatheses and thromboembolic disorders are frequently encountered in veterinary emergency and critical care practice
60 custom-made, identical 5 mL aliquots of canine platelet-rich plasma (PRP) collected by apheresis from a single canine platelet donor were obtained from a commercial veterinary blood bank.a At collection, the PRP had a platelet count of 700,000 cells/μL
Data from many of the TEG and ROTEM variables were normally distributed, but some were not, the data are summarized in the figures by median, interquartile range, minimum-maximum

Summary

Introduction

Patients with bleeding diatheses and thromboembolic disorders are frequently encountered in veterinary emergency and critical care practice. Ex vivo rotational viscoelastic tests of coagulation, namely thromboelastography (TEG) and thromboelastometry (ROTEM), provide a global assessment of hemostasis that integrates both the cellular and plasma components of the hemostatic system,[1] which may enhance understanding of the nature[2] and severity[3] of the coagulation disturbances seen in veterinary patients.[4] The TEG and ROTEM analysis systems employ a similar test principle and provide comparable, not identical, results.[5,6] These tests are proposed to better reflect the cell-based model of hemostasis,[7] which may enable assessment of hemorrhage risk in the clinical setting better than routine plasma based assays.[3,8] Such monitoring is recommended in select human perioperative scenarios.[9]

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Conclusion