Dialysis Technician Practice Exam

Which is the primary method of solute removal during hemodialysis?

1. Filtration

2. Evaporation

3. Diffusion

4. Absorption

The correct answer is: Diffusion

During hemodialysis, diffusion is the primary method utilized for solute removal. This process involves the movement of solutes across a semipermeable membrane from an area of higher concentration to an area of lower concentration. In the context of hemodialysis, the blood containing waste products and toxins flows on one side of the dialysis membrane, while a dialysis solution (dialysate) with a lower concentration of these solutes flows on the opposite side. This concentration gradient facilitates the diffusion of harmful substances out of the blood and into the dialysate, effectively cleansing the blood. The other methods listed do not play the primary role in solute removal during hemodialysis. Filtration pertains to the separation of particles based on size and is not the main mechanism for solute clearance in this therapy. Evaporation involves phase changes of liquids to gases, which is not relevant in the dialysis process, while absorption refers to the process by which one substance takes up another, which does not accurately represent the solute removal in hemodialysis. Thus, diffusion is the key mechanism driving the successful removal of waste products from the bloodstream during treatment.