Albumin

Function

Albumin is the most abundant protein found in blood plasma, produced exclusively by the liver. It serves two primary functions: maintaining oncotic pressure (which prevents fluid from leaking out of blood vessels into surrounding tissues) and acting as a carrier protein for hormones, vitamins, and drugs. Because of its high concentration, it is a primary indicator of nutritional status and hepatic synthetic function.

Why it is Ordered

Physicians order an albumin test as part of a Liver Function Test (LFT) or Comprehensive Metabolic Panel (CMP). It is used to screen for or monitor liver disease (like cirrhosis or hepatitis) and kidney disease (like nephrotic syndrome, where albumin is lost in the urine). It is also a hallmark marker for assessing malnutrition in hospitalized patients or those with chronic illnesses.

Associated Conditions

• Liver Cirrhosis: Reduced production of albumin due to liver scarring.
• Nephrotic Syndrome: The kidneys' filters are damaged, allowing albumin to leak into urine.
• Inflammatory Bowel Disease (IBD): Protein-losing enteropathy where albumin is lost through the gut.
• Ascites: Low albumin levels lead to fluid accumulation in the abdominal cavity.

Interpretation in Context

Albumin has a long half-life (about 20 days), meaning it reflects the body's status over the past few weeks rather than acute, immediate changes. Therefore, it is better for monitoring chronic conditions than acute injuries.