LIVER FUNCTION TESTS

Course overview

THE LIVER HAS A SIGNIFICANT ROLE IN METABOLISM, DIGESTION, DETOXIFICATION, AND ELIMINATION OF SUBSTANCES FROM THE BODY. THE LIVER FUNCTION TESTS TYPICALLY INCLUDE ALANINE TRANSAMINASE (ALT) AND ASPARTATE TRANSAMINASE (AST), ALKALINE PHOSPHATASE (ALP), GAMMA-GLUTAMYL TRANSFERASE (GGT), SERUM BILIRUBIN, PROTHROMBIN TIME (PT), THE INTERNATIONAL NORMALIZED RATIO (INR), TOTAL PROTEIN AND ALBUMIN. THESE TESTS CAN HELP DETERMINE AN AREA OF THE LIVER WHERE DAMAGE MAY BE TAKING PLACE AND, DEPENDING ON THE PATTERN OF ELEVATION, CAN HELP ORGANIZE A DIFFERENTIAL DIAGNOSIS. ELEVATIONS IN ALT AND AST DISPROPORTION TO ELEVATIONS IN ALKALINE PHOSPHATASE AND BILIRUBIN DENOTE HEPATOCELLULAR DISEASE. AN ELEVATION IN ALKALINE PHOSPHATASE AND BILIRUBIN IN DISPROPORTION TO ALT AND AST WOULD CHARACTERIZE A CHOLESTATIC PATTERN. THE ACTUAL FUNCTION OF THE LIVER CAN BE GRADED BASED ON ITS ABILITY TO PRODUCE ALBUMIN AS WELL AS VITAMIN K-DEPENDENT CLOTTING FACTORS.