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COVID-19 and Coagulation

By Ellie Nixon | 24th March 2021

COVID-19, first identified in Wuhan, China in December of 2019, has become a worldwide pandemic with widespread illness and mortality and a profound impact on society, culture, and the global economy. (1)

As a company who specialise in haemostasis testing, Hart Biologicals stress the importance of continued anticoagulation monitoring with the ongoing global pandemic as it is an important aspect of the patient's wellbeing. 

COVID-19 has threatened millions of lives worldwide with thromboembolic disease. Many critically ill COVID-19 positive patients have suffered major thrombotic events, prompting clinicians to evaluate hypercoagulability outside of traditional coagulation testing. (2) Therefore, there is an urgent need to understand the rate of bleeding and thrombotic manifestations associated with COVID-19 coagulopathy, as well as the clinical utility of abnormal coagulation testing to predict risk for bleeding, thrombosis, and severity of illness amongst patients. (1)

Alby Pattison, Hart Bio's founder said: “In times like these, people are looking at specialised companies and Hart Biologicals prides itself on being able to react to the needs of customers. Companies like Hart play a role in illuminating exactly what’s going on.”


COVID-19 and Platelets 

Coagulopathy is one of the most significant prognostic factors in COVID-19 and COVID-19 associated coagulopathy is a major challenge with a very high incidence of thromboembolic complications. (3) In a study conducted to assess overall primary haemostatic function at various stages of COVID-19, (4) it found that platelets are thought to participate in immune response to infection early in COVID-19 disease, at the expense of their hemostatic function.

In many situations, the standard coagulation tests fail to detect this state of hypercoagulability in COVID-19 since clotting times are either not affected, or only mildly affected. (5) From this, antiplatelet therapy is considered for treatment of COVID-19 disease but a measurement of overall primary hemostatic function should be considered prior to initiation of antiplatelet therapy. (4). However, patients with abnormal primary hemostatic function may not benefit from antiplatelet therapy, and may be at increased bleeding risk.

Notably, some COVID-19 patients may also have an increased bleeding risk due to imbalances in platelet production and consumption and other coagulation disorders. It is under investigation whether bleeding complications might occur in a specific subset of COVID-19 patients (medication, comorbidities) or at a specific stage of the disease (severe, late stage). (6)

Alby said: “Platelets are a key part of Harts offering, platelet function testing has always been a key part of the company. It’s a specialised area for testing and finding that there are issues around clotting, as well as platelet function issues, will actually help Hart Biologicals to grow both its custom base and show how specialised it is in that area.”

Hart are experts in platelet function testing, and provide full-range tests for use in the laboratory as well as on point-of-care devices.


COVID-19 and T-TAS

As COVID-19 infection is in association with variations in primary hemostatic function, it is beneficial to measure the treatment effect of COVID-19 patients receiving antiplatelet therapy.

The T-TAS 01 can be used to measure overall primary hemostatic function in COVID-19 patients. It is also able to detect abnormal primary hemostatic function in COVID 19 patients (Significantly lower AUC in patients taking antiplatelet therapy).

Baseline T-TAS 01 PL assay measurements may be useful for physicians to understand primary hemostatic function prior to administering antiplatelet therapy in COVID-19 patients. Physicians might adjust their treatment approach if they know that the patient already has abnormal primary hemostatic function, and they may monitor this activity over time. (4)

Alby continued: “T-TAS has already been used in some covid studies. The original thought was that platelets were hyperreactive or adding to the clotting issues that you see in patients. The most recent T-TAS study finds that platelet function as a clotting function is reduced.

The theory behind that is that platelets play a part in many biological processes within the bloodstream, not just clotting. From this, the platelets are being used in the immune system. Platelets play different roles in covid, it's not a hyper clotting reactivity but a hyper immune response reactivity.”

Fujimori-Kogyo’s innovative flow based coagulometer, the T-TAS system is a platelet aggregation test device that uses an automated microchip flow chamber system to evaluate thrombogenicity in whole blood and has been developed as an easy-to-use system for quantitative analysis of thrombus formation. 



  1. Hanny Al-Samkari et al. (2020) COVID-19 and coagulation: bleeding and thrombotic manifestations of SARS-CoV-2 infection. Blood. Available from:
  2. Christina Creel-Bulos et al. (2021) Fibrinolysis Shutdown and Thrombosis in a COVID-19 ICU. Available from:
  3. Klaus Görlinger, M.D,  Jerrold H. Levy, M.D., F.A.H.A., F.C.C.M. (2021) COVID-19-Associated Coagulopathy. Available from:
  4. Ghirardello et al. (2021) TTAS 01 PL Assay in COVID-19 Patients. COVID-19 Publication. Thromb Haemost
  5. Klaus Görlinger (2021) The Role of Rotational Thromboelastometry during the COVID-19 Pandemic: A Narrative Review. Available from:
  6. Ajay Gandhi & Klaus Görlinger (2020) Coagulopathy in COVID-19: Connecting the Dots. Available from: