Which process involves altering the composition of blood using a dialyzer?

The process that involves altering the composition of blood using a dialyzer is hemodialysis. In hemodialysis, the blood is circulated through a dialyzer, which is also known as an artificial kidney. The dialyzer contains a semipermeable membrane that allows certain substances to pass through while retaining larger molecules like blood cells and proteins. This selective separation enables the removal of waste products, excess electrolytes, and fluids from the blood, thereby purifying it and balancing its composition.

In contrast, reabsorption refers to the process by which certain substances are absorbed back into the bloodstream after filtration in the kidneys. Filtration is a broader term that generally describes the separation of particles from fluids, but it does not specifically involve altering blood composition as hemodialysis does. Diffusion is a fundamental principle that describes the movement of particles from regions of higher concentration to those of lower concentration, which occurs within the dialyzer during the hemodialysis process but does not encompass the overall treatment method itself. Therefore, hemodialysis is the specific process that encapsulates the mechanism of altering blood composition using a dialyzer.