What are liver function tests?
As the liver performs it’s various functions it makes a number of chemicals that pass into the bloodstream and bile. Various liver disorders alter the blood level of these chemicals. Some of these chemicals can be measured in a blood sample. Some tests that are commonly done on a blood sample are called ‘LFTs’ (liver function tests). These usually measure the following. • Alanine transaminase (ALT). This is an enzyme that helps to process proteins. (An enzyme is a protein that helps to speed up chemical reactions. Various enzymes occur in the cells in the body.) Large amounts of ALT occur in liver cells. When the liver is injured or inflamed (as in hepatitis), the blood level of ALT usually rises. • Alkaline phoshpatase (ALP). This enzyme occurs mainly in liver cells next to bile ducts, and in bone. The blood level is raised in some types of liver and bone disease. • Albumin. This is the main protein made by the liver, and it circulates in the bloodstream. The ability to make albumin (
