nit, but this is usually accomplished with plasma donation (plasmapheresis) rather than blood donation. You can donate plasma much more frequently (2x/week) vs blood (once per 2 months), thought the volume taken for each is roughly similar.
The filters used must be a specific size, so how micro, are micro plastics? If they keep breaking into smaller pieces, wouldn't they be cell sized too?
And thus, pass cell sized filters?
“Excuse me, did this blood come from a vegan? I couldn’t possibly accept blood that isn’t 100% organic, free range, and —-“ (transcript ends, patient died)
The only feasible way I see for removal is via donation or some form of hemodialysis. As the saying goes, the solution for pollution is dilution (or at least in the medical sense!)
You don't need to feel guilty. Microplastics are pervasive to the point where everybody already has them in their blood, so people receiving blood with them in it are getting any noticeably net harm done to them. If you're in need of a blood transfusion the alternative is usually death, so all things considering maintaining the status quo of microplastic levels already in you isn't the worst thing ever.