Assessment of the analytical performances and sample stability on ST Genesia system using the STG-DrugScreen application

Abstract

Background: Thrombin generation testing has been used to provide information on the coagulation phenotype of patients. The most used technique is the calibrated automated thrombogram (CAT) but it suffers from a lack of standardization, preventing its implementation in routine. The ST Genesia is a new analyzer designed to assess thrombin generation based on the same principle as the CAT. Unlike the CAT system, the ST Genesia is a benchtop, fully automated analyzer, able to perform the analyses individually and not by batch, with strict control of variables such as temperature and volumes, ensuring, theoretically, maximal reproducibility.

Objectives: This study aimed at assessing the performance of the STG-DrugScreen application on the ST Genesia analyzer. We also aimed at exploring stability of plasma samples after freezing and defining a reference normal range.

Results: Results demonstrated the excellent interexperiment precision of the ST Genesia and confirmed that the use of a reference plasma helps reducing the inter-experiments variability. Stability revealed that plasma samples are stable for at least 11 months at -70°C or lower, except for those containing low molecular weight heparins which have to be tested within 6 months. Freezing had no effect on the majority of thrombin generation parameters except on time to peak.

Conclusions: Our results suggest an easy implementation of thrombin generation with the use of ST Genesia in the routine laboratory. This will facilitate the design of multicentric studies and enable the establishment of reliable and evidence-based thresholds, which may improve the management of patients treated with anticoagulants.

Keywords: anticoagulants; blood coagulation tests; clinical laboratory techniques; normal range; reproducibility.

Conflict of interest statement

The study was financed by Diagnostica Stago group. Among the authors, J. Douxfils is chief executive officer and founder of QUALIblood s.a. and reports personal fees from Diagnostica Stago, Roche, Roche Diagnostics, and Daiichi‐Sankyo, outside the submitted work. F. Mullier reports institutional fees from Diagnostica Stago, Werfen, Nodia, Sysmex, and Bayer. He also reports speaker fees from Boehringer Ingelheim, Bayer Healthcare, and Bristol‐Myers Squibb‐Pfizer, all outside the submitted work. The other authors have no conflicts of interest to disclose.

© 2019 The Authors. Journal of Thrombosis and Haemostasis published by Wiley Periodicals, Inc. on behalf of International Society on Thrombosis and Haemostasis.

Figures

Figure 1

Stability of the different thrombin generation parameters. The 100% rejection limit (RL) has been defined as the maximal allowable error (MAE). For the endogenous thrombin potential (ETP), the MAE was 20% and for the lag time, time to peak, and the peak height; the MAE was 18% based on the data from the precision study. The Y‐intercept was used to determine the adjusted RL (upper adjusted RL = 100 + Y‐intercept – lower adjusted RL = −100 + Y‐intercept). The 95% confidence interval of the linear regression (blue hashed zone) do not cross the adjusted RL, which means that the samples are stable over the analyzed period (i.e., 11 months for healthy subject and 10 months for anticoagulated patients)

Figure 2

Stability results for samples from patients treated with low molecular weight heparin (LMWH). The upper 95% confidence interval limit of the linear regression crosses the adjusted rejection limit (RL) after 6 months determining the maximal stability of the samples