Manual reuse involves the cleaning of a dialyzer by hand. Willem Kolff was the first to construct a working dialyzer in 1943. Kolff was the first to construct a working dialyzer in 1943. This forms the "blood compartment" of the dialyzer. The hemodialysis machine pumps the patient's blood and the dialysate through the dialyzer. However, dialysis solution is also run through the dialysate compartment of the dialyzer. Dialyzer membranes come with different pore sizes. The dialyzer is composed of thousands of tiny hollow synthetic fibers. The dialyzer is the piece of equipment that actually filters the blood. The dialyzer may either be discarded after each treatment or be reused. Dialyzer technology initially outpaced the ability of clinicians to apply it to patients. If done right, dialyzer reuse can be very safe for dialysis patients. The dialyzer is semi-disassembled then flushed repeatedly before being rinsed with water. Dialyzer Reuse is a practice that has been around since the invention of the product. Dialyzer membranes used to be made primarily of cellulose (derived from cotton linter).