A-249 Evaluation of three cartridge-based analyzers for viscoelastic testing

Abstract

Viscoelastic Testing (VET) can provide information about the status of coagulation factors, platelet count, platelet function, and fibrinolysis in fresh whole blood and is used in various critical care settings. Our current VET method, Haemonetics TEG 5000 (5000) (Boston, MA) is being discontinued in the next few years. As potential replacements, we evaluated 3 cartridge-based VET analyzers: Werfen ROTEM Sigma Thromboelastometry System (Sigma) (Bedford, MA), Haemonetics TEG 6S Hemostasis System (6S), and Hemosonics Quantra Hemostasis Analyzer (Quantra) (Durham, NC). These cartridge-based VET analyzers can be used at the point of care or in the laboratory. For our evaluation, we focused on 1 cartridge type per method: ROTEM sigma complete + hep on Sigma, Global Hemostasis-HN on 6S, and QPlus on Quantra. We collected fresh Na Citrate tubes (N=69) from laboratory volunteers. Working in sets of 3, tubes were analyzed native and spiked with drugs (heparin, Eptifibatide, Argatroban, Bivalirudin, tPA) intended to affect clot initiation. We calculated the percentage of clot initiation times (R parameter on 6S, CT parameter on Sigma and Quantra) outside each platform’s reportable range. We timed a subset of samples to determine average time to clot initiation and clot strength (A20 parameter on Sigma, MA on 6S and CS by Quantra). In addition to freshly collected samples, we analyzed residual clinical Na Citrate tubes (N=25) from operating room patients. We compared error rates between the 3 methods. A small group of laboratory staff provided user feedback on each analyzer. Percentage of results outside reportable clot initiation range/max times (6, 17, and 8 minutes for Sigma CT, 6S R, and Quantra CT) was 23% (16/69) on Sigma, 38% (26/69) on 6S and 13% (9/69) on Quantra. Average time to first result and clot strength for Sigma (N=11) was 9.1 and 21.7 minutes, 6S 8.9 and 29.1 minutes, and Quantra 6.5 and 11.3 minutes. Overall error rates were 3% (3/101) for both 6S and Sigma and 8% (8/104) for Quantra. On Sigma, the 3 errors indicated partial sample aspiration; recollection would be required. The errors on 6s occurred while inserting the cartridge and required a system reboot to resolve. On Quantra, all 8 samples with errors gave partial results but would have required recollection to obtain complete results. Laboratory staff appreciated the ease of sample loading on Sigma and Quantra, though were concerned that loading the whole 2.7 mL Na Citrate tube could lead to an increase in redraws for errors or sample issues. Sample loading by pipette on 6S may increase the potential for exposures, but staff liked that the smaller sample volume required for the 6S would allow use of the smaller volume 1.8 mL Na Citrate tube. They found the speed to results on the Quantra to be a potential advantage. Analytical performance of all 3 platforms was relatively similar and could provide the needed coagulation measures to clinical providers. Time to clot initiation and clot strength, reportable range, error rates and user feedback are important considerations when choosing a VET platform.