Liver Testing

The following markers are commonly used to evaluate liver function and assess disease.

• Alkaline phosphotase (ALP)
• Alanine transaminase (ALT)
• Aspartate amino transferase (AST)
• Gamma-glutamyl transferase (GGT)
• Lactate dehydrogenase (LDH)
• Bilirubin
• Albumin
• Total protein

Additionally, hematology tests may provide some indication of disease states, including:

• Peripheral blood film
• Coagulation testing

Other testing may be performed for specific liver-related diseases.

• Hepatitis B
• Hepatitis C
  • anti-HCV antibody testing
  • HCV RNA nucleic acid testing (quantitative or qualitative)

Overview

Elevated liver markers can indicate liver disorders or be due to other causes as they are often non-specific

• AST may be increased due to liver disease, or due to damage to cardiac or skeletal muscle
  • Associated with liver disorders including hepatitis
  • Moderately increased in alcoholic cirrhosis - tends to be 2x that of ALT
• ALT is found mainly in liver, but also in heart and skeletal muscle
  • Often increased with liver diseases
  • Highest in viral hepatitis
• GGT is found in liver, along with other areas like the kidney, brain, prostate, and pancreas
  • Most sensitive for liver disease, but not very specific!
  • Associated with bile duct obstruction and chronic alcoholism
• ALP non-specific
• LDH consists of 5 isoenzymes, and is not specific

Hepatitis C

• anti-HCV antibody testing detects current or past infection (detectable at 8-11 weeks)
• HCV RNA testing detects current infection (detectable at 1-2 weeks)