asymptomatic raised ALT

Last reviewed 09/2023

The apparently well patient with chronically elevated aminotransferase levels is a medical challenge. A knowledge of the differential diagnosis permits rational investigation in such cases.

The causes of asymptomatic chronically elevated aminotransferase activity include:

  • alcohol abuse
  • drugs
  • chronic hepatitis: B and C
  • steatosis and non-alcoholic steatosis
    • non-alcoholic fatty liver disease (NAFLD) includes a wide spectrum of liver pathology, ranging from fatty liver alone to the more severe nonalcoholic steatohepatitis (1)
      • NAFLD is the most common cause of chronically elevated LFTs in the United States in both diabetic and nondiabetic individuals
        • with respect to patients with NAFLD, 60-95% are obese, 28-55% have type 2 diabetes, and 20-92% have hyperlipidemia (2)
  • autoimmune hepatitis
  • haemochromatosis
  • Wilson's disease
  • alpha1-antitrypsin deficiency

Non-hepatic causes include:

  • coeliac disease
  • inherited and acquired muscle diseases
  • exercise


  1. Angulo P. Nonalcoholic fatty liver disease. N Engl J Med 2002;346: 1221-31.
  2. Harris EH.Elevated Liver Function Tests in Type 2 Diabetes.Clinical Diabetes 2005; 23:115-119.