Albumin is the most important contributor to the maintenance of plasma colloid oncotic pressure; deficiency results in oedema.

It is an important non-specific carrier protein for molecules such as fatty acids, calcium, unconjugated bilirubin, thyroxine and urate. It may carry drugs that can displace these endogenous substances; for example, salicylates and sulphonamides may displace bilirubin.

Albumin may be separated from other plasma proteins by serum electrophoresis; albumin runs furthest towards the anode followed by alpha, beta and gamma globulins.