Newbie question - why can't our blood be filtered? (CLL)

Dear nurses :slight_smile: This question came from a dear family member when we were discussing my Chronic lymphocytic leukaemia (CLL). She said, if you are making too many white blood cells, why can’t they be filtered out like we do for people on dialysis?

Well I have no idea why! (But obviously we can’t, or it would be done…) I told her my cells are also defective, and compared it to a factory churning out quantity instead of focusing on quality. Is that on the right track? Thanks so much :slightly_smiling_face:


Dear @Calathea,
This is a really interesting question, I do not honestly know the answer and I would encourage you to chat this through with your treating team for clearer insight.

My personal thoughts on this (and it isn’t scientific, just my thoughts) would be, with dialysis the purpose is to filter the blood on behalf of the kidneys to stop a build up of high levels of electrolytes which could be dangerous. In a person with healthy kidneys they would do this job and then the body excretes this naturally.

With Chronic lymphocytic leukaemia (CLL) your bone marrow is making the leukaemic cells and these can be sat in the marrow and aren’t always circulating in your blood. To try and remove the leukaemic cells wouldn’t be possible with a dialysis machine as separating cells is an intricate process. There are machines that separate blood in a process called apheresis but this unfortunately would not fix the underlying problem in the bone marrow and therefore leukaemia cells would continue to be created, plus you wouldn’t want to filter out all white cells as we need the healthy ones.
A final thought would be that with Chronic lymphocytic leukaemia (CLL) there are different options to control the disease and I would think in advanced kidney disease dialysis is the only option!

I will reiterate, this is my guess at an explanation but I am sure a clinician can tell you the exact reasons why it isn’t treated this way.

Best Wishes, Heidi J (Support Services Nurse)


That’s a really good question @Calathea !!!


Thanks for taking a shot at it, Heidi! Your explanation makes sense :slightly_smiling_face: