A small group of doctors are among a growing global movement backing “blood washing” as a treatment for long COVID, which has seen thousands of patients travel to Europe for the expensive and experimental procedure.

The treatment involves HELP (heparin induced extracorporeal LDL precipitation) apheresis — where blood is passed over a heparin filter — which is normally used as a last resort for patients with hard-to-treat lipid disorders.

The theory is that the therapy breaks up so-called microclots that some believe are the cause of ongoing fatigue, chest pain and other symptoms in COVID-19 long-haulers.

Patients are also prescribed anticoagulant therapy including aspirin, clopidogrel, apixaban, heparin and dabigatran and IV vitamins.