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Original Research
Thromboelastography in COVID-19 patients: An observational study in the South African context
Submitted: 05 November 2024 | Published: 26 June 2025
About the author(s)
Bavinash Pillay, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South AfricaSarah A. van Blydenstein, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; and, Department of Internal Medicine, Faculty of Health Sciences, Chris Hani Baragwanath Hospital, Johannesburg, South Africa
Shahed Omar, School of Clinical Medicine, Department of Critical Care, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; and, Department of Critical Care, Faculty of Health Sciences, Chris Hani Baragwanath Hospital, Johannesburg, South Africa
Abstract
Background: Coronavirus disease 2019 (COVID-19) increases the risk of venous thromboembolism, requiring monitoring of low molecular weight heparin (LMWH) via a time-consuming, costly and often unavailable test – anti-factor Xa (anti-Xa). An affordable, rapid point-of-care alternative, the thromboelastogram, is available, but performance comparisons to anti-Xa are lacking.
Objective: This study evaluated the relationship between anti-Xa and thromboelastogram in patients with COVID-19 receiving LMWH.
Methods: This was a retrospective study of patients with COVID-19 receiving LMWH at Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa, between November 2020 and January 2021. Blood samples tested with thromboelastogram and anti-Xa were drawn at three timepoints (one prior to and two after administration of LMWH). Thromboelastogram parameters comprised reaction time (R-time; onset of testing to the start of clot formation), kinetics time (K-time; start of clot formation until the clot reached 20 mm), and thromboelastogram coagulation index (overall coagulation status of whole blood).
Results: Forty-two patients with COVID-19 (15 male and 27 female) met the study criteria. There was a statistically significant, low to moderate correlation (Spearman’s correlation coefficient [rs 0.43, p = 0.014]) between anti-Xa and thromboelastogram coagulation index. A statistically significant moderate correlation (rs 0.52, p = 0.002) between anti-Xa and R-time, and a statistically significant low correlation (rs 0.35, p = 0.049) between anti-Xa and K-time, were found. All correlations were 48 h post admission.
Conclusion: Thromboelastogram coagulation index, R-times and K-times had a statistically significant association with anti-Xa levels in patients with COVID-19. Further research is required regarding their clinical utility.
What this study adds: Thromboelastograms may represent a more cost-effective and accessible option to the conventional anti-Xa test in patients receiving LMWH. However, future research with larger sample sizes, varying disease profiles, and severity of illness is required.
Keywords
Sustainable Development Goal
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