Medical Matters > Micro-clots

ME Essential Spring 2024


Has there been any progress with the research that has been looking at the presence of ‘micro-clots’ in Long Covid and possibly in ME/CFS as well?

I know that people are still travelling abroad to be treated with apheresis to remove these small clots at expensive private clinics. But I understand that no such treatment is available here in the UK – either privately or on the NHS.


The simple answer is no – the role of micro-clots in having a role in causing both Long Covid and ME/CFS remains uncertain and controversial.

As you are probably aware, a research group headed by Professor Resia Pretorius in South Africa are claiming that there are small particles in the blood called microclots in people with Long Covid. These small clots are obstructing blood flow in small blood vessels called capillaries. The consequent lack of blood supply and oxygenation of vital tissues is then involved in symptom development.

This has led to some doctors prescribing anticoagulants (blood clot removal medication) or a process called apheresis (where a machine filters the blood
rather like kidney dialysis) to remove these micro-clots. However, doctors who are experts in blood clotting remain generally unconvinced because the findings have yet to be repeated by any other reputable research groups.

In addition, the chemical composition of these microclots, which involves two proteins called amyloid and fibrin, is not the same as normal blood clots, which contain cells called platelets and fibrin.

Consequently, the use of anticoagulants (which don’t degrade amyloid) and apheresis, both of which have the potential to cause serious side effects, are not available on the NHS.

The research in South Africa has concentrated on the possible role of micro-clots in Long Covid but it has been suggested that they could also be involved in ME/CFS.

At the moment this ME/CFS connection remains highly speculative and unproven. The MEA is following these developments very closely and if a link with Long Covid is firmly established then the Ramsay Research Fund would be very willing to fund research involving people with ME/CFS


Information provided by The ME Association should not be construed as medical advice. Don't assume any new or worsened symptoms are simply the result of having ME/CFS or Long Covid. We recommend that any information you deem relevant is discussed with your NHS GP as soon as possible. It is important that you seek personalised medical advice from the GP who is in charge of your care and who knows you well.

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