The liver is a large organ that takes up drugs and toxic substances from the blood and renders them harmless. It produces proteins, including enzymes and blood clotting factors, helps maintain hormone balance and stores vitamins. The liver produces bile, a fluid that is transported through ducts to the gallbladder to be stored and then to the small intestine to help digest fats.
Liver disease can be detected, evaluated and monitored by combinations of up to five tests measured at the same time on a blood sample. These may include:
Alanine aminotransferase (ALT) – an enzyme mainly found in the liver; the best test for detecting hepatitis
Aspartate aminotransferase (AST) – an enzyme found in the liver and a few other places, particularly the heart and other muscles in the body
Total bilirubin – measures all the yellow bilirubin pigment in the blood
Conjugated bilirubin, measures the form made only in the liver and is often requested with total bilirubin in infants with jaundice
Alkaline phosphatase (ALP) – an enzyme related to the bile ducts; often increased when they are blocked, either inside or outside the liver
Albumin – measures the main protein made by the liver and tells how well the liver is making this protein
Total protein – measures albumin and all other proteins in blood, including antibodies made to help fight off infections
