investigations of fatty liver

Last reviewed 05/2022

Initial laboratory tests include:

  • liver enzymes
    • aminotransferase levels
      • in non alcoholic fatty liver disease –
        • alanine aminotransferase (ALT) levels exceeding those of aspartate aminotransferase (AST) – AST:ALT <0.8 (>0.8 with more advanced disease)
      • in alcoholic fatty liver disease
        • AST:ALT ratio >1.5
    • gamma glutamyl transferase (GGT)
    • alkaline phosphatase (ALP) – may be increased
  • MCV – increased
    • raised MCV and serum gamma GT suggest alcohol abuse; note that GGT may be raised in non-alcoholic steohepatitis which is not associated with alcohol abuse
  • hepatic screen for other causes of abnormal liver function tests including screening for hepatitis B, hepatitis C and haemochromatosis
  • liver imaging
    • ultrasound,
      • is the first-line imaging technique
      • causes increased echogenicity on ultrasound (compared with the lower echogenicity of the spleen or renal cortex)
      • sensitivity and specificity of detecting fatty infiltration decreases as BMI increases
    • CT or MRI will demonstrate fatty infiltration
  • liver biopsy
    • needle biopsy confirms the diagnosis and excludes irreversible disease

Additional laboratory tests may be considered in patients with chronically elevated liver enzyme levels or in those with a family history of cirrhosis and includes:

  • autoimmune studies - antinuclear antibody, smooth muscle antibody
  • α1-antitrypsin
  • ceruloplasmin
  • thyroid-stimulating hormone levels
  • NICE suggest to consider using the enhanced liver fibrosis (ELF) test in people who have been diagnosed with non-alcoholic fatty liver disease (NAFLD) to test for advanced liver fibrosis (4)

Reference: