Nikhil Prasad Fact checked by:Thailand Medical News Team Aug 25, 2026 39 minutes ago
A new study has found striking evidence that people with Long COVID may continue to have unusually fast blood-clotting activity alongside increased numbers of abnormal microclot complexes and platelet-related material in their plasma.
New research links Long COVID with faster blood clotting, increased amyloid-like microclot complexes, and elevated
platelet-associated material.
The research compared blood samples from 20 people with Long COVID and 19 healthy controls. The institutions involved included Stellenbosch University in South Africa, the Montpellier Cancer Research Institute and Montpellier University in France, and the University of Liverpool in the United Kingdom.
Blood Clotting Remained Abnormally Fast
Researchers used thromboelastography, a laboratory technique that tracks how quickly blood begins clotting, how rapidly a clot develops, and its eventual strength.
Long COVID samples showed faster clot initiation and development in both whole blood and platelet-poor plasma. Importantly, several abnormalities remained even after most platelets and blood cells had been removed.
For example, median reaction time in whole blood fell from 12.9 minutes in controls to 9.2 minutes in Long COVID. In platelet-poor plasma, it dropped even more sharply, from 17.3 to 9.4 minutes.
However, clot strength and the total amount of clot produced were not significantly different. This suggests Long COVID was associated mainly with accelerated clotting processes rather than simply producing bigger or stronger clots.
Microclots and Platelet Material Increased
The team also examined fibrinaloid microclot complexes, or FMCs. These are abnormal insoluble structures containing proteins with amyloid-like characteristics.
This Thailand
Medical News report highlights that Thioflavin T-positive FMCs were significantly more numerous in Long COVID across undiluted plasma, diluted plasma, and processed plasma pellets.
In undiluted samples, the median count increased from 678 in controls to 1,766 in Long COVID. Diluted samples showed median counts of 600 versus 990, while processed pellets showed 281 versus 527.
Platelet-associated material showed another major difference. Median platelet-marker-positive events reached 14,761 in Long COVID compared with 7,718 among controls, potentially indicating continuing platelet activity.
Interestingly, DNA-containing cellular material was not significantly increased.
More Abnormal Particles, Not Necessarily Larger Ones
Detailed analysis suggested that Long COVID was primarily associated with greater numbers of abnormal events rather than consistently larger particles.
The different materials also occupied distinctive size ranges. DNA-associated cellular material was concentrated among smaller particles, platelet-associated material peaked around platelet-sized ranges, while amyloid-bearing FMCs were proportionally more
prominent among larger structures.
Microscopy provided additional evidence that these microclot complexes were diverse. Some contained cellular material, while others appeared membrane-free and strongly amyloid-like. Congo Red staining provided further evidence supporting their amyloid characteristics.
Conclusions
The findings strengthen evidence that persistent abnormalities involving plasma clotting, platelets, and amyloid-like microclot complexes may occur in Long COVID. Larger studies and standardized testing methods are now needed to determine their clinical importance and whether these abnormalities contribute directly to symptoms or could eventually become useful treatment targets.
The study findings were published on a preprint server and have yet to be peer reviewed.
https://www.medrxiv.org/content/10.64898/2026.08.20.26360874v1
Read Also:
https://www.thailandmedical.news/articles/long-covid
Share
Tweet
Share
