What is the term for an apparatus that uses semi-permeable membranes to filter wastes from blood?

The term for an apparatus that uses semi-permeable membranes to filter wastes from blood is a dialyzer. This device is commonly used in the process of dialysis, which is a medical treatment for individuals whose kidneys are unable to effectively filter waste, toxins, and excess fluids from the blood.

The dialyzer functions by allowing blood to flow through one side of its semi-permeable membrane, while a dialysis solution or "dialysate" flows on the other side. The membrane's selective permeability enables small waste molecules and excess electrolytes to pass from the blood into the dialysate, effectively cleaning the blood without the need for a functioning kidney. For patients undergoing dialysis treatment, the use of a dialyzer is critical for managing their health and preventing complications associated with kidney failure.

In contrast, the other options do not relate to the filtration of blood. A hemostat is a tool used to control bleeding during surgical procedures, an incubator is a device used to maintain the optimal conditions for developing organisms, such as in neonatal care or microbiology, and an oximeter is a device that measures the oxygen saturation level in a person’s blood. Therefore, the dialyzer is the only apparatus listed that specializes in filtering