Albumin, Serum | Healthmatters.io (2025)

What is a serum Albumin test?

You need a proper balance of albumin to keep fluid from leaking out of blood vessels (=oncotic pressure). It also carries vital nutrients and hormones.Albumin also gives your body the proteins it needs to keep growing and repairing tissue.

A serum albumin test is a simple blood test that measures the amount of albumin in your blood. Having surgery, getting burned, or having an open wound raises your chances of having a low albumin level.

What Is Albumin?

Albumin is the most common protein found in the blood. It represents half (~50%) of the total protein content (reference range:3.8 g/dL to 4.8 g/dL) of plasma in healthy human patients.

Albumin is synthesized (= produced) by liver hepatocytes (=the major cells in the liver). Very little albumin is stored in the liver, and most of it gets rapidly excreted into the bloodstream.

Albumin has two main functions:

1. Maintenance (modulation) of appropriate oncotic pressure in the vascular system.

Albumin is responsible for much of the colloidal osmotic pressure of the blood, and hence is a very important factor in regulating the exchange of water between the plasma and the interstitial compartment, which is the space between the cells. Due to the hydrostatic pressure, water is forced through the walls of the capillaries in the tissue space. This flow of water is continuous until the osmotic pull of protein, in this case albumin molecules, causes it to stop. An abnormal deficiency of albumin can lead to water passing from the bloodstream into the tissues (edema).

2. Transporter of endogenous and exogenous (i.e. drugs) ligands.

Albumin serves as a transport protein carrying large organic anions, those such as fatty acids, hormones (cortisol and thyroxine when their specific binding globulins are saturated), bilirubin and many drugs.Severe liver disease can result in hypoalbuminemia (hypo = below, beneath), which leads to fewer available binding sites for exogenous drugs. This results in larger amounts of unbound exogenous drugs, which can lead to increased drug sensitivity. This sensitivity manifests when patients have serum albumin concentrations lower than 2.5 g/dL.

Normal range for Albumin levels:

→The normal range is 3.8 - 4.8 g/dL (38 to 48 g/L).

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples.

References:

Yuwen P, Chen W, Lv H, Feng C, Li Y, Zhang T, Hu P, Guo J, Tian Y, Liu L, Sun J, Zhang Y. Albumin and surgical site infection risk in orthopaedics: a meta-analysis. BMC Surg. 2017 Jan 16;17(1):7. doi: 10.1186/s12893-016-0186-6. PMID: 28093079; PMCID: PMC5238522.

Anderson CF, Wochos DN. The utility of serum albumin values in the nutritional assessment of hospitalized patients. Mayo Clin Proc. 1982 Mar;57(3):181-4. PMID: 6801397.

Shapiro M, Rhodes JB, Beyer PL. Malnutrition. Recognition and correction by enteral nutrition. J Kans Med Soc. 1983 Jun;84(6):341-5, 356. PMID: 6409975.

Martin Kroll, Tietz Textbook of Clinical Chemistry, Third Edition. Carl A. Burtis and Edward R. Ashwood, eds. Philadelphia, PA: WB Saunders, 1998, 1917 pp., ISBN 0-7216-5610-2.,Clinical Chemistry, Volume 45, Issue 6, 1 June 1999, Pages 913–914,https://doi.org/10.1093/clinchem/45.6.913

Moman RN, Gupta N, Varacallo M. Physiology, Albumin. [Updated 2022 Dec 26]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-.Available from: https://www.ncbi.nlm.nih.gov/books/NBK459198/

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