Ace the Certified Hemodialysis Technician Exam 2025 – Transform Lives with Your Expertise!

The correct answer is ultrafiltration. This term specifically refers to the process in dialysis where excess fluid and waste products are removed from the blood. In hemodialysis, ultrafiltration occurs when blood flows through a dialyzer, where a semipermeable membrane allows for the selective removal of water and small solutes, while retaining larger molecules like proteins and cells.

Ultrafiltration is primarily driven by the pressure gradient created across the membrane. By adjusting the pressure, dialysis technicians can control the amount of fluid removed from a patient during the procedure, which is crucial for maintaining fluid balance and preventing complications such as fluid overload.

The other terms, while related to dialysis, describe different processes. Osmosis pertains to the movement of water across a semipermeable membrane driven by concentration gradients, whereas diffusion involves the movement of solutes from an area of higher concentration to one of lower concentration. Filtration is a broader term that may not specifically describe the mechanisms involved in dialysis, making ultrafiltration the most precise term in this context.