Albumin deficiency, or hypoalbuminemia, is an abnormally low level of the protein albumin in the blood. You might have it tested as part of a standard panel of liver function tests. The normal range for albumin is 3.5 to 4.5 mg/dL. If your albumin level is less than 3.5 mg/dL, it is considered low. Many potential causes of low albumin can be at work, including malnutrition, liver disease, kidney disease or a stress response.
Albumin is a protein produced only by the liver. In the bloodstream, it transports bilirubin, fatty acids, metals, ions, hormones and drugs. If your albumin is low, it can affect how medications work. Low albumin can also cause edema, or swelling of the tissues. Other symptoms include muscle weakness, fatigue, cramps and poor appetite. In hospitalized patients, a low serum albumin level is associated with increased risk of morbidity and mortality. Treatment of hypoalbuminemia focuses on treatment of the underlying cause of the albumin deficiency, supported by adequate dietary intake of protein and calories.
Hypoalbuminemia can be caused by chronic malnutrition. If your protein intake is inadequate, your liver will make less albumin. Because the body draws albumin from tissues to keep the serum albumin level stable, a low serum level reflects depletion of tissue albumin stores. In the U.S., chronic malnutrition is seen more frequently in older patients who are institutionalized, patients with advanced chronic disease or anorexia, and malnourished children. To treat hypoalbuminemia caused by malnutrition, both protein and calorie intake must be adequate. If your calorie intake is too low, the protein you eat will be used as an energy source.
Because albumin is synthesized by hepatic cells, hypoalbuminemia might be a sign of liver damage or disease. Albumin synthesis can be reduced with cirrhosis, alcoholism, hepatitis B, hepatitis C, hepatic cancer or autoimmune liver disease. If you have low albumin due to liver problems, you might have ascites, in which the abdomen becomes swollen with fluid. To check for liver problems, your health care provider will check liver function tests, look for signs of jaundice, and might order a CT scan of the abdomen and a liver biopsy.
Sometimes, serum albumin levels are low because albumin is being lost from the body. This can happen if you have a kidney disease such as nephrotic syndrome. Tiny blood vessels in the kidneys – called glomeruli – become damaged and allow albumin to leak out into the urine. Albumin can also be lost from the body due to malabsorption syndromes such as protein-losing enteropathy, inflammatory bowel disease or lymphoma, in which protein is lost in the stool.
Hypoalbuminemia is often caused by an acute or chronic inflammatory response to stress. Infections, surgery, trauma or burns can lead to an increase in cytokine release and reduced albumin production. Decreased albumin synthesis, increased albumin breakdown, a redistribution of albumin in body fluids and greater losses of albumin can all contribute to lower serum levels with the stress response.