Intra‐ and inter‐centre standardisation of thromboelastography (TEG^®)

Abstract

SummaryThromboelastography is used for assessment of coagulation and to guide administration of blood products peri-operatively. There is currently no method of standardisation in the UK, nor an approved method of proving quality. We investigated the reproducibility of thromboelastography by testing whole blood with no coagulation abnormality in three phases. Where a single operator performed multiple assays on the same blood sample at a single location, we found considerable variation, with 21% of R-and 25% of K-time measurements lying outside a set tolerance range (median AE 20%). Where samples were analysed by different operators in a single location, this finding was repeated. Where blood was transported in a citrated form for simultaneous analysis in multiple locations, results were more consistent, suggesting improved stability. Across all phases of testing there was good reproducibility of the maximum amplitude. Further examination of the results indicated less variation where analysis was performed on blood taken from the same kaolin vial compared with results from different vials. Our preliminary study indicates that R-and Ktimes may be highly variable, which we hypothesise may be due to variable mixing of blood and kaolin. We intend to repeat this study in the context of coagulopathy, where variability in results could potentially impact upon transfusion practice.

Management of Trauma-Induced Coagulopathy with Thrombelastography

“…42 This is thought to be due to age related changes and variations in phenotypes of hemostasis seen across populations, as well as instrument operator variability. Thus, generic reference ranges may not be applicable to individual centers and should be locally produced.…”

Global assays of hemostasis

“…The results showed that the instruments are more interchangeable than originally reported [62]. However, there is still much debate as to what the appropriate initiators and parameters are to evaluate for consistent and reliable results [63–66]. Currently, the variability requires multiple daily calibrations and trained personnel to limit the potential for user error.…”

New-Generation Thromboelastography: Comprehensive Evaluation of Citrated and Heparinized Blood Sample Storage Effect on Clot-Forming Variables

“…[4][5][6][7] The disadvantages of viscoelastic hemostatic assays have historically included a relatively high coefficient of variation, poorly standardized methodologies, and limitations on the specimen stability of native whole blood samples. [8][9][10] In the pediatric setting, an advantage of the TEG is the relatively small sample volume needed, but a disadvantage is the difference in reference ranges between infants, especially newborns, and adults. 10 A variety of assays containing different activators can be run on a TEG device, providing insights into different aspects of coagulation.…”