Liver function tests are a group of blood tests used to determine the function and health of a patient's liver. they usually include
Albumin - Albumin is made by the liver and is cheap and easy to test for. Low levels are typically caused by cirrhosis
AST and ALT - Although neither is specific to the liver, if both levels are high, it does point to liver damage.
Alkaline phosphatase - High levels usually indicate a blockage in the ducts inside or leading from the liver.
Total and direct bilirubin - The liver is responsible for breaking down bilirubin that is not bound to albumin. The tests measure all bilirubin (bound and unbound - total) and that not bound to albumin (direct). Depending on the level of each, it can point to the failure of the liver to process it (all high) or excrete it (only direct is high).
Gamma glutamyl transpeptidase - Slightly high levels are not a significant clinical finding, but when combined with the results of other tests can point to exact causes of liver problems
Prothrombin time - The liver creates most of the substances involved in clotting. High prothrombin time can point to liver damage.
5' Nucleotidase - Another test to determine if the ducts from the liver may be obstructed
Serum glucose - The liver is responsible for converting other sugars to glucose. Low glucose levels in a patient with otherwise normal sugar levels can point to liver damage.