Albumin is a small, globular protein that is the most abundant protein in blood plasma, accounting for about 50-60% of total plasma proteins. It is synthesized primarily in the liver and plays several essential roles in maintaining proper bodily function and homeostasis.
The main functions of albumin include:
- Maintaining colloid osmotic pressure: It contributes to the regulation of blood volume and pressure by maintaining the colloid osmotic pressure. This pressure prevents excessive movement of fluid from blood vessels into surrounding tissues, ensuring that blood remains within the circulatory system.
- Transport of various substances: It serves as a carrier protein for several molecules, including hormones, fatty acids, and drugs. By binding to these substances, albumin helps transport them throughout the body and regulate their concentrations in the blood.
- Binding and buffering of ions: It bind to ions like calcium and helps regulate their concentrations in the blood. It also acts as a buffer, helping to maintain the acid-base balance in the body.
- Antioxidant properties: It has antioxidant properties and can scavenge free radicals, which can help protect cells from oxidative damage.
Abnormal albumin levels can be indicative of various medical conditions:
- Low albumin levels (hypoalbuminemia): Low albumin levels can result from liver disease, malnutrition, kidney disease (nephrotic syndrome), inflammation, or increased loss of albumin through the gastrointestinal tract or skin. Hypoalbuminemia can lead to edema (swelling) due to a decrease in colloid osmotic pressure.
- High albumin levels (hyperalbuminemia): High albumin levels are relatively rare and can be caused by dehydration, which leads to a concentration of proteins in the blood, or occasionally due to increased production by the liver.
Albumin levels can be measured as part of a comprehensive metabolic panel or a liver function test to help diagnose and monitor various diseases and conditions, such as liver disease, kidney disease, and malnutrition.
