Pre-albumin is a blood protein made primarily by the liver. Its role is to transport thyroxine (the main thyroid hormone) and vitamin A throughout the body. Its dosage is often used in addition to other biological markers to assess the severity of malnutrition.
What is serum pre-albumin?
Serum pre-albumin, also known as transthyretin, is a protein produced mainly in the liver and in the cells of the thyroid gland. It serves as a transporter for certain thyroid hormones and for vitamin A.”Measurement of serum pre-albumin is often used as a nutritional status indicator of a person, since its concentration decreases rapidly in the event of malnutrition or protein deficiencyexplains Doctor Alexis Guérin, medical biologist. This is why serum pre-albumin is often used in addition to other biological markers to assess the severity of malnutrition and the response to nutritional therapy”.
The determination of serum pre-albumin is done by a simple blood test. It is often performed in combination with other biological markers to assess a person’s nutritional status. “The collected serum is then analyzed in the laboratory to determine the concentration of pre-albumin“, continues the biologist.
Pre-albumin in the blood: the standards
Serum pre-albumin standards may vary slightly from lab to lab depending on the analytical method used. “In general, the normal concentration of serum pre-albumin is between 20 and 40 mg/dL (milligrams per deciliter)”, answers the specialist. However, standards can vary according to age, gender and health status general of a person. “For example, older people may have lower serum pre-albumin concentrations due to decreased liver function or chronic inflammation“.
Low pre-albumin: causes
There are several factors that can explain a low concentration of serum pre-albumin. Among them :
► “Since pre-albumin is often used as a biological marker of a person’s nutritional status, a low serum pre-albumin concentration may indicate malnutrition or insufficient protein intake“, explains the doctor.
► “THE chronic inflammatory diseases such as rheumatoid arthritis, Crohn’s disease or ulcerative colitis can also cause a drop in serum pre-albumin due to increased inflammatory processes”.
► Pre-albumin is produced mainly in the liver. “Liver failure can cause a decrease in the synthesis of pre-albumin and therefore a low concentration in the blood”.
► The Systemic Response Inflammatory Syndrome (SIRS) can be caused by infections, trauma or major surgery. “It may cause a drop in serum pre-albumin due to release of inflammatory cytokines and inhibition of protein synthesis“.
► Finally, “certain types of cancer, such as lung cancermay lead to lower serum pre-albumin due to increased consumption of protein by cancer cells“.
Pre-albumin is often used as a biological marker of nutritional status
High pre-albumin: causes
A high serum pre-albumin concentration is less common than a low pre-albumin concentration. However, it can be associated with certain conditions. “Hyperthyroidism can increase the synthesis of pre-albumin by the liverthereby resulting in a high concentration of serum pre-albumine”, observes the biologist. Similarly, “Iare corticosteroids may stimulate the synthesis of pre-albumin and thus lead to a high concentration of the protein in the blood”.
Pre-albumin and undernutrition
Pre-albumin is often used as biological marker of a person’s nutritional status. Indeed, a low concentration of serum pre-albumin is an indicator of acute malnutrition. “Pre-albumin is also used in the follow-up of malnourished patients benefiting from nutritional therapy, assures Dr. Guérin. Malnutrition is a pathological condition characterized by deficiency of essential nutrients such as proteins, fats and carbohydrates. Undernutrition can be caused by a lack of intake of essential nutrients or in contexts of digestive malabsorption (digestive inflammation, cancers, etc.).
Thanks to Doctor Alexis Guérin, medical biologist, director of the Cerballiance laboratories in Manche and Vire Normandie.