Albumin refers generally to any protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 that is water soluble

Solubility

Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...

, which is moderately soluble in concentrated salt solutions, and experiences heat denaturation

Denaturation (biochemistry)

Denaturation is a process in which proteins or nucleic acids lose their tertiary structure and secondary structure by application of some external stress or compound, such as a strong acid or base, a concentrated inorganic salt, an organic solvent , or heat...

. They are commonly found in blood plasma

Blood plasma

Blood plasma is the straw-colored liquid component of blood in which the blood cells in whole blood are normally suspended. It makes up about 55% of the total blood volume. It is the intravascular fluid part of extracellular fluid...

, and are unique to other blood proteins

Blood proteins

Blood proteins, also termed serum proteins or plasma proteins, are proteins found in blood plasma. Serum total protein in blood is 7g/dl...

 in that they are not glycosylated

Glycoprotein

Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...

. Substances containing albumin, such as egg white

Egg white

Egg white is the common name for the clear liquid contained within an egg. In chickens it is formed from the layers of secretions of the anterior section of the hen's oviduct during the passage of the egg. It forms around either fertilized or unfertilized egg yolks...

, are called albuminoids.

A number of blood transport protein

Transport protein

A membrane transport protein is a membrane protein involved in the movement of ions, small molecules, or macromolecules, such as another protein across a biological membrane. Transport proteins are integral membrane proteins; that is they exist within and span the membrane across which they...

s are known to be evolutionarily related, including serum albumin

Serum albumin

Serum albumin, often referred to simply as albumin is a protein that in humans is encoded by the ALB gene.Serum albumin is the most abundant plasma protein in mammals. Albumin is essential for maintaining the osmotic pressure needed for proper distribution of body fluids between intravascular...

, alpha-fetoprotein

Alpha-fetoprotein

Alpha-fetoprotein is a protein that in humans is encoded by the AFP gene....

, vitamin D-binding protein and afamin.
For patients with low blood volume, there is no evidence that albumin reduces mortality when compared with cheaper alternatives such as normal saline, or that albumin reduces mortality in patients with burns and low albumin levels.