What is the function of albumin?

Study liver anatomy and function with our medical students test. Engage with detailed multiple choice questions, each with hints and explanations. Prepare effectively for your test!

Albumin is the most abundant plasma protein synthesized by the liver, and its main job is to keep fluid inside the blood vessels. It creates colloid (oncotic) pressure, which draws water back into the vasculature from the surrounding tissues. This helps maintain blood volume and prevents edema. If liver function is impaired and albumin production falls, oncotic pressure drops, edema and even ascites can develop because fluid leaks into the interstitial spaces more easily.

Albumin also serves as a carrier for various substances (such as certain fatty acids, bilirubin, and drugs) and has some antioxidant properties, but these roles are secondary to its role in maintaining vascular fluid balance. The other options describe functions that are typical of enzymes (speeding reactions), ferritin or transferrin (iron storage/transport), and immune components like antibodies (fighting infections), not primarily albumin.

So the best answer is: maintains oncotic pressure in the vascular system.