Dual duties for dialysis machines.?

Why can't doctors use dialysis machines with special filters to cure more diseases of the blood? Couldn't they use UV light, antibiotic or chemically impregnated filters to treat diseases such as leukemia or aids etc. ?

That's a good question and the answer has to do with the size of molecules. In your blood are important molecules and compounds like calcium, potassium, hormones, etc., and if a dialysis filter was created that was big enough to remove bacteria and viruses, it would also remove those important molecules.

The part about antibiotics and chemicals would be useless, because it wouldn't make any difference whether the blood passed through a chemically or antibiotic coated filter or if those same things were injected directly into the blood stream. Why take the blood out, expose them to the chemicals, and then put the blood back in, when you could just put the chemicals directly into the bloodstream.

As for the UV light - there is something similar, which I think is called plasmaphoresis, which I think is like dialysis, but exposes the blood to UV light or something similar. I can't remember what it is effective against, but it's only certain things.