Albumin and Hypoalbuminemia

Albumin

• Albumin is produced exclusively in the liver and comprises about half of the blood serum protein.
• Causes of hypoalbuminemia include decreased hepatic synthesis, increased protein losses, kidney disease, protein-losing enteropathy, and severe burns.
• Decreased serum albumin levels are not seen in acute liver failure because it takes several weeks of impaired albumin production before the serum albumin level drops.

Bilirubin

• Bilirubin is an orange-yellow pigment found in bile, produced from the breakdown of hemoglobin in red blood cells.
• Metabolism of bilirubin involves breaking down hemoglobin into heme, which is then converted into unconjugated bilirubin (indirect bilirubin) in the macrophages of the spleen.
• Unconjugated bilirubin is not soluble in water and is bound to albumin and sent to the liver for conjugation.
• Conjugated bilirubin (direct bilirubin) is soluble in water and is excreted into the bile and eventually into the small intestine.

Functions of Bilirubin

• Bilirubin is measured in neonates to assess the severity of neonatal jaundice.
• Bilirubin levels are also measured to assess liver disease, bile duct blockage, or hemolytic anemia.
• Normal bilirubin levels in adults are 0.2-1.2 mg/dl (total bilirubin) and 0.0-0.2 mg/dl (direct bilirubin).
• In neonates, bilirubin levels less than or equal to 8 mg/dl are considered normal.

Jaundice

• Jaundice is a yellowish discoloration of the skin, conjunctival membranes, and other mucous membranes caused by hyperbilirubinemia (increased levels of bilirubin in the blood).
• Jaundice is classified into three categories: pre-hepatic, hepatic, and post-hepatic, depending on the location of the pathology affecting the physiological mechanism.

Gamma Glutamyl Transferase (ɣ-GT)

• ɣ-GT is elevated in about 75% of chronic drinkers, and the level is correlated with the duration of alcohol intake or dose.
• ɣ-GT is also elevated in hepatic malignancies, toxic hepatitis, and biliary disease.
• ɣ-GT is moderately elevated in acute pancreatitis and pancreatic malignancy associated with hepatobiliary obstruction.