Therapeutic plasma exchange (TPE) was tested in a gold standard trial for Long COVID, appears to be a dud

A Spanish study concluded:

There were no diferences between groups in any of the efficacy parameters evaluated. Whereas TPE is safe, it did not lead to any discernible improvement of the PCC in this clinical trial.

This treatment is sometimes called Plasma exchange, apheresis, plasmapheresis, etc.

Published results

https://www.nature.com/articles/s41467-025-57198-7