Albumin is a carbohydrate‑free protein, which constitutes 55‑65 % of total plasma protein. It maintains oncotic plasma pressure, and is also involved in the transport and storage of a wide variety of ligands and is a source of endogenous amino acids. Albumin binds and solubilizes various compounds, e. g. bilirubin, calcium and long-chain fatty acids. Furthermore albumin is capable of binding toxic heavy metal ions as well as numerous pharmaceuticals, which is the reason why lower albumin concentrations in blood have a significant effect on pharmacokinetics.
Hyperalbuminemia is of little diagnostic significance except in the case of dehydration. Hypoalbuminemia occurs during many illnesses and is caused by several factors: compromised synthesis due either to liver disease or as a consequence of reduced protein uptake; elevated catabolism due to tissue damage (severe burns) or inflammation; malabsorption of amino acids (Crohn’s disease); proteinuria as a consequence of nephrotic syndrome; protein loss via the stool (neoplastic disease). In severe cases of hypoalbuminemia, the maximum albumin concentration of plasma is 2.5 g/dL. Due to the low osmotic pressure of the plasma, water permeates through blood capillaries into tissue (edema). The determination of albumin allows monitoring of a controlled patient dietary supplementation and serves also as an excellent test of liver function.
Reference intervals according to Tietz
|0-4 days||2.8-4.4 g/dL||28-44 g/L||421-662 µmol/L|
|4 days-14 years||3.8-5.4 g/dL||38-54 g/L||572-812 µmol/L|
|14-18 years||3.2-4.5 g/dL||32-45 g/L||481-677 µmol/L|
|18-60 years||3.5-5.2 g/dL||35-52 g/L||527-782 µmol/L|
|60-90 years||3.2-4.6 g/dL||32-46 g/L||481-692 µmol/L|
|>90 years||2.9-4.5 g/dL||29-45 g/L||436-677 µmol/L|
|millimole per liter||mmol/L = mM/L = millimol/L|
|micromole per liter||µmol/L = mcmol/L = umol/L = µM/L = mcM/L = uM/L = micromol/L|
|gram per liter||g/L = gram/L|
|gram per deciliter||g/dL = gram/dL|
|gram per 100 milliliters||g/100mL = gram/100mL|
|gram percent||g% = gram%|
|milligram per milliliter||mg/mL = millig/mL = milligram/mL|
Lab units Conversion Calculator. Convert Albumin level to mmol/L, µmol/L, mcmol/L, umol/L ,µM/L, mcM/L, uM/L, micromol/L, g/L, g/dL, g/100mL, g%, mg/mL. Clinical laboratory units online conversion from conventional or traditional units to Si units. Table of conversion factors for Albumin.