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Liver Function Tests




  • AST and ALT are enzymes that are commonly used in conjunction to identify active hepatocellular injury.
  • AST is found in the liver, cardiac muscle, skeletal muscle, kidneys, brain, pancreas, lungs, leukocytes and erythrocytes.
  • ALT is found mainly in the liver, and is more specific for hepatocellular injury.

Elevated Aminotransferases

    • Causes of Elevated Transaminases

    • Hepatocellular Injury

    • Viral hepatitis - A, B, C, E, HSV, EBV, CMV, VZV
    • Alcoholic liver disease - alcoholic hepatitis, steatohepatosis, cirrhosis
    • Non-alcoholic hepatosteatosis (fatty liver disease)
    • Drug or toxin-induced liver disease - paracetamol, NSAIDs, statins, ciprofloxacin, azole antifungals, methotrexate, amiodarone, isoniazid, phenytoin, sulfonylureas, rifampicin, anabolic steroids, cocaine, ecstasy, PCP, glues, solvents, certain herbal remedies
    • Vascular disease - ischaemic hepatitis, portal venous thrombosis, congestive cardiac failure
    • Infiltrative disease - sarcoidosis, amyloidosis, tuberculosis, Hodgin lymphoma, liver metastases
    • Autoimmune liver diseases - autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis
    • Haemochromatosis
    • Wilson’s disease
    • Alpha-1 antitrypsin deficiency
    • Hepatocellular carcinoma
    • Non-Hepatic

    • Myopathy - vigorous exercise, myositis
    • Hypothyroidism
    • Coeliac disease
    • Interpretation

    • Mild derangement (<5x normal)Non-alcoholic steatohepatosis, chronic viral hepatitis, liver metastases, drugs
    • Moderate derangement (5-20x normal)Chronic viral hepatitis, alcoholic hepatitis, autoimmune hepatitis
    • Severe derangement (>20x normal)Acute viral hepatitis, drug-induced hepatitis, ischaemic hepatitis
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