Evaluation of the Lysis Timer to Investigate ‘Global Fibrinolysis Capacity’ in Plasma

M. Bareille¹, M. Hardy², B. Chatelain¹, T. Lecompte³, F. Mullier¹

¹Université Catholique de Louvain, Hematology laboratory, Namur Thrombosis and Hemostasis Center (NTHC), CHU UCL Namur, Yvoir, Belgium, ²Université Catholique de Louvain, Anesthesiology Department, Namur Thrombosis and Hemostasis Center (NTHC), CHU UCL Namur, Yvoir, Belgium, ³Departments of Medicine, Division of Angiology and Haemostasis, Geneva University Hospitals, and Geneva Platelet Group (GpG), Faculty of Medicine, University of Geneva, Geneva, Switzerland

Abstract Number: PB0423

Meeting: ISTH 2021 Congress

Theme: Fibrinogen, Fibrinolysis and Proteolysis » Fibrinolytic Factors and Inhibitors

Background: There is currently no universal and standardized test available for plasma fibrinolytic activity. The ‘global fibrinolysis capacity’ (GFC) assay performed with the Lysis Timer instrument (SD Innovation; reagents and internal quality controls from Hyphen Biomed) does not have the euglobulin clot lysis time (ECLT) related preanalytical constraints.

Aims: Our primary aims were i) to investigate the influence of the temperature used to keep the samples after sampling (4°C versus ambient temperature); ii) and that of a freezing-thawing cycle; and iii) to establish a preliminary reference range for GFC. Our secondary aim was to compare results of GFC with ECLT.

Methods: Influence of sample storage temperature and a freezing-thawing cycle were studied with fresh plasma samples from 30 healthy adult volunteers. Reference range was established on fresh plasma samples from 21 healthy adult volunteers. Method comparison was performed with 77 samples (healthy volunteers n = 34, patients with personal history of bleedings n = 43).

Results: There was no difference between GFC assessed in plasma samples processed on melting ice or at room temperature (p = 0.17), whereas GFC assessed in frozen-thawed plasma samples was prolonged when compared to fresh samples (p = 0.002) (Figure 1).

Influence of preanalytical factors (A. Sample storage temperature; B. Freeze-thawing cycle)
Preliminary reference interval ranged from 29 (90%CI = [27-32]) to 50 (90%CI = [46-53]) minutes.GFC and ECLT were weakly correlated (ρ = 0.229, p = 0.04), with a poor agreement (κ = 0.03, 95%CI = [-0.154-0.221]) (Table 1).

	GFC
ECLT	hyperfibrinolysis (n)	within reference range (n)	hypofibrinolysis (n)
hyperfibrinolysis (n)	0	9	0
within reference range (n)	0	52	11
hypofibrinolysis (n)	0	3	2

Agreement table between euglobulin clot lysis time (ECLT) and global fibrinolysis capacity (GFC)

Conclusions: Sample storage temperature had no influence on the result. Reference ranges need to be established for fresh and frozen samples. Shorter than 1-hour reference interval enables the use of GFC in emergency cases. Finally, GFC and ECLT showed a weak correlation and a poor agreement, likely explained by plasma absence of fibrinolysis inhibitors such as PAI-1 in the euglobulin fraction.

To cite this abstract in AMA style:

Bareille M, Hardy M, Chatelain B, Lecompte T, Mullier F. Evaluation of the Lysis Timer to Investigate ‘Global Fibrinolysis Capacity’ in Plasma [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/evaluation-of-the-lysis-timer-to-investigate-global-fibrinolysis-capacity-in-plasma/. Accessed November 29, 2021.

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