Viral Hepatitis and Liver Disease Website Course
Evaluating Liver Test Abnormalities
Understanding the Pathophysiology of Liver Disease
for Health Care Providers
Tests of Liver Injury
Using the paradigm that the liver may be divided into two morphological subunits, liver injury can also be considered as injury to the hepatocytes (hepatocellular injury) and injury to the biliary system, resulting in inability to secrete/excrete bile (cholestasis). Although many causes of liver disease give rise to either a predominantly hepatocellular or a predominantly cholestatic disease, many others may give rise to "mixed" injury.
Note: The degree of test abnormalities does not correlate with the severity of liver dysfunction.
Tests of Hepatocellular Injury
With hepatocyte cell death, the intracellular enzymes leak out, causing an elevation in their serum levels. The common tests of this group include aspartate aminotransaminases (AST), and alanine aminotransferase (ALT).
Tests of Cholestatic Injury
An impairment in bile flow leads to cholestasis (literally, static bile). The common tests that reflect cholestasis include alkaline phosphatase, gamma glutamyltransferase (GGT) and 5'nucleotidase.