Process of high purity albumin production

A process is provided for the preparation of albumin which has extremely low levels of or is essentially free of colorants, metal ions, human proteins, host proteins, fragments of albumin, polymers or aggregates of albumin and viruses, and which is essentially non-glycated, relatively high in free thiol and with an intact C-terminus. The process comprises passing albumin (preferably expressed and secreted by transformed yeast) through positive mode cation exchange and then positive mode anion exchange chromatography. Other steps may also be employed, for example ultrafiltration, gel permeation chromatography, affinity chromatography binding the albumin (for example using blue dyes) and affinity chromatography binding contaminants (for example using an aminophenylboronic acid resin). Elution of albumin, with a compound having affinity for albumin, from a material having no specific affinity for albumin is also disclosed, as is removal of ammonium ions with a counter-ion.